Polymerizable compound, polymer, positive-resist composition, and patterning process using the same

ABSTRACT

The present invention provides a polymer which has at least one or more of a repeating unit represented by a following general formula (1a), a repeating unit represented by a following general formula (2a) and a repeating unit represented by a following general formula (3b), and a repeating unit represented by a following general formula (1c), and a positive resist composition which contains as a base resin the polymer. Thereby, there can be provided a positive-resist composition having high sensitivity and high resolution in exposure with a high energy beam, wherein line edge roughness is small since swelling at the time of development is suppressed, and the residue after development is few

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a positive-resist composition,especially to a chemically amplified positive-resist composition,suitable as a micropatterning material, especially for the VLSImanufacture, or for manufacture of a photomask pattern, which shows ahigh alkali dissolution-rate contrast before and after exposure, highsensitivity and high resolution, a reduced line edge roughness, and anoutstanding etching resistance in exposure with a high energy beam.

2. Description of the Related Art

In recent years, with a tendency that integration and speed have becomehigher in LSI, a tendency that a pattern rule becomes finer progressesrapidly. In the background that the tendency that a pattern becomesfiner has progressed quickly, there are a tendency that NA of aprojection lens has become higher, improvement in resist performance,and a tendency that a wavelength has become shorter. Especially atendency that a wavelength becomes shorter from i line (365 nm) to KrF(248 nm) causes a big change, and thus mass production of a device with0.18 μm rule is also made possible. The chemically amplifiedpositive-resist composition in which an acid is used as a catalyst (forexample, see Japanese Patent Publication No. 2-27660 and Japanese PatentApplication Laid-open (KOKAI) No. 63-27829) has an outstanding featurein the tendency that resolution and sensitivity of resist become higher,and thus has become a main resist composition especially fordeep-ultraviolet lithography.

The resist composition for KrF excimer lasers has began to be usedgenerally for a 0.3-micron process, and it has also been began to beapplied to mass-production of 0.18-micron rule via a 0.25-micron rule.Furthermore, examination of a 0.15 micron rule has also been started,and the tendency that a pattern becomes finer is acceleratedincreasingly. It is expected that a design rule should be 0.13 μm orless with a tendency that a wavelength becomes shorter from a KrFexcimer laser to an ArF excimer laser (193 nm). However, it was hard touse novolak and polyvinyl phenol resin which have been usedconventionally as a base resin for resist, since it has a quite strongabsorption near the wavelength of 193 nm. Then, aliphatic resins such asacrylic resins or cycloolefin resins have been examined to ensuretransparency and a required dry etching resistance (for example, seeJapanese Patent Application Laid-open (KOKAI) No. 9-73173, JapanesePatent Application Laid-open (KOKAI) No. 10-10739, Japanese PatentApplication Laid-open (KOKAI) No. 9-230595, and Internationalpublication No. 97/33198).

Among them, the resist based on (meth)acrylic base resin with a highresolution has been examined. As (meth)acrylic resin, the combination ofthe (meth)acrylic which has methyl adamantane ester as an acid labilegroup unit and the (meth)acrylic which has an ester of a lactone ring asan adhesion group unit has been proposed (for example, see JapanesePatent Application Laid-open (KOKAI) No. 9-90637). Furthermore,norbornyl lactone has been proposed as an adhesion group by which anetching resistance is reinforced (for example, see Japanese PatentApplication Laid-open (KOKAI) No. 2000-26446 and Japanese PatentApplication Laid-open (KOKAI) No. 2000-159758).

Reduction of line edge roughness and reduction of residue afterdevelopment are mentioned as one of the problems in ArF lithography.Swelling at the time of development is mentioned as one of the causesfor line edge roughness. Although polyhydroxy styrene used as a resistfor KrF lithography is hardly swelled since phenol thereof is a weaklyacidic group and has a moderate alkali solubility, swelling at the timeof development is easily caused in the polymer containing a highlyhydrophobic alicyclic group, since it is dissolved with a carboxylicacid with high acidity.

Here, the amount of swelling during development has been reported bymeasurement of the development characteristics of the resist accordingto the QCM (Quartz Crystal Microbalance) method (for example, see Proc.SPIE Vol. 3999 p2 (2000)). Although swelling of the film duringdevelopment cannot be observed by a conventional optical interferencethickness-measurement method, it is possible to observe increase inweight of the film by swelling according to the QCM method, since theweight change of a film is measured electrically. In the reference,swelling of the ArF resist based on cycloolefin polymer is disclosed.Significant swelling is observed especially in the case that acarboxylic acid is used as an adhesion group.

SUMMARY OF THE INVENTION

The present invention has been made in order to solve such problems. Theobject of the present invention is to provide a positive-resistcomposition showing high sensitivity and high resolution in exposurewith a high energy beam, reduced line edge roughness due to suppressedswelling at the time of development, and reduced residues afterdevelopment.

To achieve the above mentioned object, the present invention provides apolymerizable compound represented by a following general formula (1),

wherein R⁴¹ is a hydrogen atom or a methyl group, R⁴² is a fluorine atomor a trifluoro methyl group, R⁴³ is a hydrogen atom or a monovalent acylgroup, R⁴⁴ and R⁴⁵ each independently represents a hydrogen atom or afluorine atom, R¹⁶ is a single bond or a linear or branched alkylenegroup having 1–4 carbon atoms, X¹ is any one of a methylene group, anethylene group, an oxygen atom and a sulfur atom, and Y² is —O— or—C(═O)—O—.

The present invention provides a polymer which has at least one or moreof a repeating unit represented by a following general formula (1a), arepeating unit represented by a following general formula (2a) and arepeating unit represented by a following general formula (3b), and arepeating unit represented by a following general formula (1c),

wherein R¹ represents any one of a hydrogen atom, a methyl group and—CH₂CO₂R⁶, R² represents any one of a hydrogen atom, a methyl group and—CO₂R⁶, R¹ and R² in the repeating units (1a) and (2a) may be the sameor different, R³ to R⁵ each independently represent a monovalenthydrocarbon group having 1–15 carbon atoms which may contain a heteroatom, R⁶ represents a hydrogen atom or a linear, branched or cyclicalkyl group having 1–15 carbon atoms, R¹⁵ represents any one of ahydrogen atom, a methyl group and —CH₂CO₂R⁶, R¹⁴ represents any one of ahydrogen atom, a methyl group and —CO₂R⁶, R¹⁶ represents a single bondor a linear or branched alkylene group having 1–4 carbon atoms, R¹⁷represents a fluorine atom or a trifluoro methyl group, R¹⁸ representsany one of a hydrogen atom, an acyl group having 1–10 carbon atoms andan acid labile group, R²¹ and R²² each independently represent ahydrogen atom or a fluorine atom, R²³ and R²⁴ each independentlyrepresent a hydrogen atom or a linear or branched alkyl group having 1–6carbon atoms, R²⁵ is a linear, branched or cyclic alkyl group having1–20 carbon atoms, Y² is —O— or —C(═O)—O—, Z¹ is a bridged cyclichydrocarbon group having 4–10 carbon atoms, which may have —O— and/or—S—, and a1, a2, c, and b3 fall within the range that 0≦a1≦0.8,0≦a2≦0.8, 0≦b3≦0.8, 0.1≦a1+a2+b3≦0.8, and 0<c≦0.9.

In this case, it is desirable that the repeating unit represented by thegeneral formula (1c) is a repeating unit represented by a followinggeneral formula,

wherein R¹⁴, R¹⁵, R¹⁶, R¹⁷, R¹⁸, R²¹, R²², Y², a same as mentionedabove, and X¹ is any one of a methylene group, an ethylene group, anoxygen atom and a sulfur atom.

Such a polymer of the present invention can be easily obtained, forexample, by polymerizing the novel polymerizable compound represented bythe above-mentioned general formula (1), and any one or more compoundsof the compound for obtaining the repeating unit represented by theabove-mentioned general formula (1a), the compound for obtaining therepeating unit represented by the above-mentioned general formula (2a)and the compound for obtaining the repeating unit represented by theabove-mentioned general formula (3b). And the positive-resistcomposition which contains the above-mentioned polymer as a base resinshows a sharply high alkali dissolution-rate contrast before and afterexposure in exposure with a high energy beam, shows a high sensitivityand a high resolution, and shows a reduced line edge roughness sinceswelling at the time of development is suppressed. Furthermore, etchresidues thereof is few, and etching resistance thereof is excellent.Therefore, since it has these characteristics, practicality is veryhigh, and it is suitable for the VLSI manufacture, or formicropatterning material in production of a photomask pattern.

And it is desirable that the positive-resist composition of the presentinvention further contains an organic solvent and an acid generator toserve as a chemically amplified resist composition.

As described above, if the polymer of the present invention is used as abase resin and an organic solvent and an acid generator are furtherblended therein, there can be obtained the chemically amplifiedpositive-resist composition, which shows very high sensitivity since adissolution rate of the above-mentioned polymer in a developer in anexposed area is accelerated by an acid catalysis, and is very suitableas a micropatterning material for the VLSI manufacture or the like whichhas been demanded in recent years.

In this case, the positive-resist composition of the present inventionmay further contains a dissolution inhibitor.

By blending a dissolution inhibitor in the positive-resist compositionas described above, the difference of the dissolution rate in theexposed area and the non-exposed area can be enlarged further, and aresolution can be raised further.

Moreover, in the positive-resist composition of the present invention, abasic compound and/or a surfactant may be further blended as anadditive.

For example, a diffusion rate of an acid in a resist film can besuppressed and a resolution can be further improved, by adding a basiccompound as descried above, and an application property of a resistcomposition can be further improved or controlled by adding asurfactant.

Such a resist composition of the present invention can be used for aprocess of forming a pattern on a semiconductor substrate, a masksubstrate, or the like by performing, at least, a step of applying theresist composition to the substrate, a step of exposing the appliedresist composition with a high energy beam after heat-treatment, and astep of developing the exposed resist composition by using a developer.

Of course, development may be conducted after conducting the heattreatment after exposure, and other various processes, such as anetching process, a resist removing process, a cleaning process or thelike may be performed.

In this case, the above-mentioned high energy beam may have a wavelengthin the range of 180 nm–200 nm.

The resist composition which contains the polymer of the presentinvention as a base resin can be suitably used especially in exposurewith a high energy beam with a wavelength in the range of 180 nm–200 nm,and sensitivity is excellent at the exposure wavelength in this range.

As explained above, the present invention provides a polymer obtained bycopolymerizing a monomer which is an ester having adamantane with anacid leaving property and/or a monomer which is an ester having anacetal type acid leaving group, and a monomer which is a compound forobtaining a repeating unit having a substituted or unsubstituted alcoholhaving a fluorinated alkyl group or a fluorine atom at an α position. Byblending this polymer as a base resin in the resist composition, thereis provided the material which shows high sensitivity and highresolution, a reduced small line edge roughness, reduced residues afterdevelopment, and suppression of swelling during development measuredaccording to QCM method or the like. Therefore, it is possible toprovide a positive-resist composition, such as a chemically amplifiedpositive-resist composition suitable especially as a micropatterningmaterial for the VLSI manufacture or for production of a photomaskpattern.

Furthermore, according to the present invention, the novel polymerizablecompound for obtaining such a polymer of the present invention isprovided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph which shows the result of the measurement which wasperformed according to the QCM method as for the resist formed by theresist composition of Example 1.

FIG. 2 is a graph which shows the result of the measurement which wasperformed according to the QCM method as for the resist formed by theresist composition of Comparative Example 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The inventors of the present invention have studied thoroughly in orderto obtain a positive resist composition which shows a high sensitivityand high resolution, a reduced line edge roughness since swelling at thetime of development is suppressed, and reduced residues afterdevelopment in exposure with a high energy beam.

There is disclosed (meth)acrylate which has an adamantane ester with anacid leaving property, for example, in Japanese Patent ApplicationLaid-open (KOKAI) No. 9-73173.

Moreover, examination of the resist using the hexafluoro alcohol as anobject for F₂ lithography is performed. It has been reported that ahexafluoro alcohol has an acidity equivalent to phenol, and swellingthereof in a developer is small (J. Photopolym. Sci. Technol., Vol. 16,No. 4, p523 (2003)). Moreover, polynorbornene having a hexafluoroalcohol, and α trifluoromethyl acrylate which has pendant hexafluoroalcohol have been introduced there, and exposure characteristics inexposure with the ArF excimer laser are also introduced.

Then, the inventors have applied it, and found that a positive-resistcomposition which shows a high sensitivity and high resolution, reducedline edge roughness due to swelling at the time of development, andreduced residues after development can be provided by using as a baseresin a polymer obtained by using a combination of (meth)acrylate whichis an ester having adamantane with acid leaving property and an adhesiongroup which has alkali solubility such as hexafluoro alcohol. Therebythe present invention has been completed.

Namely, the polymer according to the present invention is a polymerwhich has at least one or more of a repeating unit represented by afollowing general formula (1a), a repeating unit represented by afollowing general formula (2a) and a repeating unit represented by afollowing general formula (3b), and a repeating unit represented by afollowing general formula (1c),

wherein R¹ represents any one of a hydrogen atom, a methyl group and—CH₂CO₂R⁶, R² represents any one of a hydrogen atom, a methyl group and—CO₂R⁶, R¹ and R² in the repeating units (1a) and (2a) may be the sameor different, R³ to R⁵ each independently represent a monovalenthydrocarbon group having 1–15 carbon atoms which may contain a heteroatom, R⁶ represents a hydrogen atom or a linear, branched or cyclicalkyl group having 1–15 carbon atoms, R¹⁵ represents any one of ahydrogen atom, a methyl group and —CH₂CO₂R⁶, R¹⁴ represents any one of ahydrogen atom, a methyl group and —CO₂R⁶, R¹⁶ represents a single bondor a linear or branched alkylene group having 1–4 carbon atoms, R¹⁷represents a fluorine atom or a trifluoro methyl group, R¹⁸ representsany one of a hydrogen atom, an acyl group having 1–10 carbon atoms, andan acid labile group, R²¹ and R²² each independently represent ahydrogen atom or a fluorine atom, R²³ and R²⁴ each independentlyrepresent a hydrogen atom or a linear or branched alkyl group having 1–6carbon atoms, R²⁵ is a linear, branched or cyclic alkyl group having1–20 carbon atoms, Y² is —O— or —C(═O)—O—, Z¹ is a bridged cyclichydrocarbon group having 4–10 carbon atoms, which may have —O— and/or—S—, and a1, a2, c, and b3 fall within the range that 0≦a1≦0.8,0≦a2≦0.8, 0≦b3≦0.8, 0.1≦a1+a2+b3≦0.8, and 0<c≦0.9.

In this case, it is desirable that the repeating unit represented by thegeneral formula (1c) is a repeating unit represented by a followinggeneral formula,

wherein R¹⁴, R¹⁵, R¹⁶, R¹⁷, R¹⁸, R²¹, R²², Y² and c are the same asmentioned above, and X¹ is any one of a methylene group, an ethylenegroup, an oxygen atom and a sulfur atom.

The positive-resist composition which contains such a polymer of thepresent invention as a base resin shows, in exposure with the highenergy beam, a significantly high alkali dissolution-rate contrastbefore and after exposure, high sensitivity and high resolution, areduced line edge roughness due to suppression of swelling duringdevelopment, reduced residues after development, and excellent etchingresistance. Therefore, because of these characteristics it is suitableas a micropatterning material especially for the VLSI manufacture or forproduction of a photomask pattern.

Illustrative examples of the monomer which is the ester shown in thegeneral formula (1a) or (2a) can be listed below, but it is not limitedto them.

Illustrative examples of the monomer which is an ester having the acidlabile group shown in the general formula (3b) can be listed below.However, it is not limited to them.

(In the formula, R¹, R², R²³, R²⁴, and R²⁵ are the same as thosementioned above.)

As the ester compound monomer for obtaining the repeating unit which hasa substituted or unsubstituted alcohol having a fluorinated alkyl groupor a fluorine atom shown in the general formula (1c), there can bementioned a polymerizable compound represented by a following generalformula (1), for example,

wherein R⁴¹ is a hydrogen atom or a methyl group, R⁴² is a fluorine atomor a trifluoro methyl group, R⁴³ is a hydrogen atom or a monovalent acylgroup, R⁴⁴ and R⁴⁵ each independently represents a hydrogen atom or afluorine atom, R¹⁶ is a single bond or a linear or branched alkylenegroup having 1–4 carbon atoms, X¹ is any one of a methylene group, anethylene group, an oxygen atom and a sulfur atom, and Y² is —O— or—C(═O)—O—.

The following compounds can illustratively be mentioned as thepolymerizable compound represented by the above-mentioned generalformula (1) and other polymerizable compounds for obtaining therepeating unit shown in the general formula (1c).

In addition, R⁴³ in the monomer before polymerization represented by thegeneral formula (1) may be the same as R¹⁸ in the repeating unitrepresented by the general formula (1c) after polymerization as above.Or it may be an acetyl group before polymerization and may be convertedto a hydroxy group by alkali hydrolysis after polymerization, and ifnecessary, a hydrogen atom of the hydroxy group may be substituted withan acid labile group thereafter.

The polymerizable compound represented by the general formula (1) can bepreferably synthesized by a synthetic process shown below. However, itis not limited to the synthetic process.

(In the formulae, R⁴¹⁻⁴⁵ are the same as those of the general formula(1), and R⁴⁶ is any one of a hydrogen atom, an alkyl group having 1–10carbon atoms, and an aryl group having 6–10 carbon atoms.)

In the 1st process (i), a compound (b′) is synthesized by Diels Alderreaction of a compound (a′) and a diene compound. Although this reactionprogresses easily under the known conditions, it is preferable that thecompound (a′) and the diene compound are mixed without solvent or in asolvent, and a reaction is progressed with heating or cooling if needed.Conventional methods such as recrystallization, chromatography anddistillation can be used in order to isolate the intended substance fromthe reaction mixture.

The compound (b′) is converted to a compound (c′) in the 2nd process(ii). This process can also be conducted by the known method.Illustratively, it can be conducted by the method by which atrifluoroacetic acid is added to the compound (b′), and then hydrolyzedor ester exchanged, or the method by which the compound (b′) issubjected to hydroboration-oxidation reaction followed by hydrolysis orester exchange. However, it is not limited thereto. In any methods, itis possible to separate the intended substance from the reaction mixtureby conventional methods such as recrystallization, chromatography, anddistillation.

The 3rd process (iii) is esterification of the compound (c′). Althoughthe reaction progresses easily under the known conditions, it ispreferable to add as a raw material the compound (c′), carboxylic acidhalide such as acryloyl chloride and methacryloyl chloride, and a basesuch as triethylamine in a solvent such as methylene chloride,sequentially or simultaneously, and be cooled if needed.

The compound (d′) can also be separated from the reaction mixtureaccording to conventional methods such as recrystallization,chromatography, and distillation.

The polymer of the present invention is characterized in that it isobtained by copolymerizing the monomers which are esters havingadamantane with an acid leaving property represented by the formulae(1a) and (2a) and/or the monomers which are esters having an acid labilegroup represented by the formula (3b), and the monomer which is acompound for obtaining a repeating unit having a substituted orunsubstituted alcohol having a fluorinated alkyl group or a fluorineatom at an α position represented by the formula (1c). Furthermore, themonomer (1d) (the repeating unit d) which is an ester having an acidlabile group other than those represented by the general formula (1a),(2a) and (3b) can be copolymerized.

(In the formula, R¹ and R² represent the same as mentioned above, andR¹⁹ represents an acid labile group.)

Next, various acid labile groups represented by R¹⁸ and R¹⁹ in thegeneral formulae (1c) and (1d) can be selected, and they may be the sameor different. They may have the structure in which hydrogen of ahydroxyl group or a hydroxy group of a carboxyl group is substitutedespecially with the group represented by the following formula (AL10), atertiary alkyl group having 4–40 carbon atoms represented by thefollowing formula (AL12), an oxoalkylgroup having 4–20 carbon atoms orthe like.

In the formula (AL10), R⁵⁰⁶ is a linear, branched or cyclic alkyl grouphaving 1–20 carbon atoms, and may contain hetero atoms, such as oxygen,sulfur, nitrogen, fluorine or the like. a5 is an integer of 0–10.

Illustrative examples of the compound represented by the formula (AL10)may include: tert-butoxy carbonyl group, tert-butoxy carbonyl methylgroup, tert-amyloxy carbonyl group, tert-amyloxy carbonyl methyl group,1-ethoxy ethoxy carbonyl methyl group, 2-tetrahydropyranyl oxycarbonylmethyl group, and 2-tetrahydrofuranyl oxycarbonyl methyl group, or thelike, and further the substituents represented by the following generalformulae (AL10)-1 to (AL10)-9.

In the formulae (AL10)-1 to (AL10)-9, R⁵¹⁴ may be the same or different,and represents a linear, branched or cyclic alkyl group having 1–8carbon atoms, or an aryl group or aralkyl group having 6–20 carbonatoms. R⁵¹⁵ does not exist or represents a linear, branched or cyclicalkyl group having 1–20 carbon atoms. R⁵¹⁶ represents an aryl group oran aralkyl group having 6–20 carbon atoms.

Further examples of the acid labile group represented by R¹⁸ and R¹⁹ inthe general formulae (1c) and (1d) may include groups represented by thefollowing general formulae (AL11)-1 to (AL11)-19, (AL11)-24 to(AL11)-33.

Examples of the tertiary alkyl group shown in the above-mentionedformula (AL12) may include: tert-butyl group, triethyl carbyl group,1-ethyl norbornyl group, 1-methyl cyclohexyl group, 1-ethyl cyclopentylgroup, tert-amyl group or the like, and those represented by thefollowing general formulae (AL12)-1 to (AL12)-16.

In the above-mentioned formula, R⁵¹⁰ may be the same or different, andrepresents a linear, branched or cyclic alkyl group having 1–8 carbonatoms, an aryl group or aralkyl group having 6–20 carbon atoms. R⁵¹¹ andR⁵¹³ do not exist, or represent a linear, branched or cyclic alkyl grouphaving 1–20 carbon atoms. R⁵¹² represents an aryl group or aralkyl grouphaving 6–20 carbon atoms.

Furthermore as shown in (AL12)-19 and (AL12)-20, a bridge may be formedin the molecule or between the molecules of the polymer, including R⁵¹⁴which is an alkylene group or arylene group with bivalent or more. R⁵¹⁰in the formula (AL12)-19 and (AL12)-20 may be the same as mentionedabove, and R⁵¹⁴ may represent a linear, branched or cyclic alkylenegroup or arylene group having 1–20 carbon atoms, and may contain heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom and thelike. b6 is an integer of 1–3.

Furthermore, R⁵¹⁰, R⁵¹¹, R⁵¹², and R⁵¹³ may have hetero atoms, such asoxygen, nitrogen, sulfur or the like. Illustratively, they may be shownby the following (AL13)-1 to (AL13)-7.

The polymeric material of the present invention indispensably containsthe repeating unit represented by the general formula (1c), and it isobtained by copolymerizing the repeating unit represented by the generalformula (1c) and one or more of the repeating units represented by thegeneral formulae (1a), (2a) and (3b). Furthermore, the repeating unitrepresented by the general formula (1d) can also be copolymerizedtherewith. Furthermore, the repeating unit which has an adhesion groupother than the repeating units represented by a general formulae (1a),(2a), (1c), (3b), and (1d) can also be copolymerized therewith.Illustratively, the repeating unit which has an adhesion group can bethe repeating unit e wherein the monomers (1e) specifically illustratedbelow are polymerized.

In the general formulae (1a), (2a), (1c), (3b), and (1d), a ratio of therepeating units a1, a2, c, b3 and d is the value such that 0≦a1≦0.8,0≦a2≦0.8, 0≦b3≦0.8, 0.1≦a1+a2+b3≦0.8, 0<c≦0.9, 0≦d≦0.8, preferably0≦a1≦0.7, 0≦a2≦0.7, 0≦b3≦0.7, 0.15≦a1+a2+b3≦0.7, 0.1≦c≦0.9, and 0≦d≦0.7.

Furthermore, when the monomer (1e) is copolymerized, the ratio of therepeating unit e is the value such that 0≦e/(a1+a2+c+b3+d+e)≦0.8,preferably 0≦e/(a1+a2+c+b3+d+e)≦0.7.

The polymer of the present invention each needs to have a weight averagemolecular weight (a measuring method is as mentioned below) of1,000–500,000, preferably 2,000–30,000. If the weight average molecularweight is too small, a heat resistance of the resist composition will bedegraded. If it is too large, an alkali solubility will be lowered, andit will become easy to cause a footing profile after pattern formation.

Furthermore, in the polymer of the present invention, when a molecularweight distribution (Mw/Mn) is large, there is a possibility thatimpurities may be observed on a pattern, or a shape of a pattern may bedegraded after exposure, since there exist both of the polymer with lowmolecular weight and the polymer with high molecular weight. So, if thepattern rule becomes finer, the influence by a molecular weight or adispersion of a molecular weight easily gets larger. Accordingly, inorder to obtain the resist composition used suitably for a micropatternsize, it is desirable to use a multi-component copolymer with a narrowmolecular weight distribution as 1.0–2.0, preferably 1.0–1.5.

Moreover, it is also possible to blend two or more polymers having adifferent composition ratio, a different molecular weight distribution,or a different molecular weight.

In order to synthesize these polymers, there is a method of adding aradical initiator to a monomer which has a unsaturated bond forobtaining the repeating units a1, a2, c, b3 and d, and the monomerrepresented by the repeating unit e in organic solvent, to performheating polymerization, and thereby, a polymer can be obtained. Examplesof the organic solvent used at the time of polymerization may include:toluene, benzene, tetrahydrofuran, diethyl ether, dioxane, and the like.Examples of the polymerization initiator may include:2,2′-azobisisobutyronitril (AIBN), 2,2′-azo bis(2,4-dimethylvaleronitrile), dimethyl 2,2-azo bis(2-methyl propionate), benzoylperoxide, lauroyl peroxide, and the like. Polymerization can beconducted preferably by heating at 50° C. to 80° C. The reaction timemay be 2 to 100 hours, preferably 5–20 hours. The acid labile group maybe used as those introduced into the monomer, or the acid labile groupmay be released by an acid catalyst once and then protected or partiallyprotected.

The positive-resist composition of the present invention may contain,organic solvent, and the compound which perceives a high energy beam andgenerates an acid (acid generator), and if necessary a dissolutioninhibitor, a basic compound, a surfactant, and other components.

Organic solvents used for the resist composition of the presentinvention, especially chemically amplified positive-resist compositioncan be any organic solvents in which a base resin, an acid generator,and other additives can be dissolved. Examples of such an organicsolvent may include: ketones such as cyclohexanone, methyl-2-n-amylketone and the like; alcohols such as 3-methoxy butanol,3-methyl-3-methoxy butanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanoland the like; ethers such as propylene glycol monomethyl ether, ethyleneglycol monomethyl ether, propyleneglycol monomethyl ether, ethyleneglycol monoethyl ether, propyleneglycol dimethyl ether, diethyleneglycoldimethyl ether and the like; esters such aspropyleneglycolmonomethylether acetate, propyleneglycol monoethyletheracetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate,tert-butyl propionate, propyleneglycol monotertbutylether acetate andthe like; lactones such as γ-butyrolactone; and the like. They can beused alone or in admixture of two or more of them. However, they are notlimitative. Among the above-mentioned organic solvents,diethyleneglycoldimethylether, 1-ethoxy-2-propanol,propyleneglycolmonomethylether acetate, and a mixed solvent thereof inwhich an acid generator in the resist component is dissolved best arepreferably used.

The amount of the organic solvent to be used is preferably 200 to 10,000parts (by weight), especially 400 to 800 parts to 100 parts of the baseresin.

Examples of the acid generator used in the present invention are asfollow:

-   i) an onium salt represented by the following general formula    (P1a-1), (P1a-2) or (P1b)-   ii) a diazomethane derivative represented by the following general    formula (P2),-   iii) a glyoxime derivative represented by the following general    formula (P3),-   iv) a bis sulfone derivative represented by the following general    formula (P4),-   v) a sulfonate of a N-hydroxy imide compound represented by the    following general formula (P5),-   vi) a β-keto sulfonic-acid derivative,-   vii) a disulfone derivative,-   viii) a nitro benzyl sulfonate derivative,-   ix) a sulfonate derivative, or the like.

(In the formulae, R^(101a), R^(101b), and R^(101c) independentlyrepresent a linear, branched or cyclic alkyl group, alkenyl group,oxoalkyl group or oxoalkenyl group each having 1–12 carbon atoms, anaryl group having 6–20 carbon atoms, or an aralkyl group or an aryloxoalkyl group having 7–12 carbon atoms. Some or all of hydrogen atomsof these groups may be substituted with an alkoxy group or the like.R^(101b) and R^(101c) may constitute a ring. In the case that theyconstitute a ring, R^(101b) and R^(101c) represent an alkylene grouphaving 1–6 carbon atoms respectively. K⁻ represents a non-nucleophiliccounter ion.) The above-mentioned R^(101a), R^(101b) and R^(101c) may bethe same or different. Illustrative examples thereof as an alkyl groupmay include: a methyl group, an ethyl group, a propyl group, anisopropyl group, n-butyl group, sec-butyl group, tert-butyl group, apentyl group, a hexyl group, a heptyl group, an octyl group, acyclopentyl group, a cyclohexyl group, a cycloheptyl group, acyclopropyl methyl group, 4-methyl cyclohexyl group, a cyclohexyl methylgroup, a norbornyl group, an adamantyl group, or the like. Illustrativeexamples of an alkenyl group may include: a vinyl group, an allyl group,a propenyl group, a butenyl group, a hexenyl group, a cyclohexenylgroup, or the like. Examples of an oxoalkyl group may include:2-oxocyclopentyl group, 2-oxocyclohexyl group, 2-oxopropyl group,2-cyclopentyl-2-oxoethyl group, 2-cyclohexyl-2-oxoethyl group,2-(4-methylcyclohexyl)-2-oxoethyl group, and the like. Examples of theoxoalkenyl group may include: 2-oxo-4-cyclohexenyl group,2-oxo-4-propenyl group and the like. Examples of an aryl group mayinclude: a phenyl group, a naphthyl group, an alkoxy phenyl group suchas p-methoxyphenyl group, m-methoxyphenyl group, o-methoxyphenyl group,an ethoxyphenyl group, p-tert-butoxyphenyl group, m-tert-butoxy phenylgroup and the like, an alkyl phenyl group such as 2-methylphenyl group,3-methylphenyl group, 4-methylphenyl group, an ethylphenyl group,4-tert-butylphenyl group, 4-butylphenyl group, a dimethyl phenyl groupand the like, an alkyl naphthyl group such as a methylnaphthyl group, anethyl naphthyl group and the like, an alkoxy naphthyl group such as amethoxy naphthyl group, an ethoxy naphthyl group and the like, a dialkylnaphthyl group such as a dimethyl naphthyl group, a diethyl naphthylgroup and the like, and a dialkoxy naphthyl group such as a dimethoxynaphthyl group, a diethoxy naphthyl group and the like. Examples of thearalkyl group may include a benzyl group, a phenylethyl group, aphenethyl group and the like. Examples of an aryl oxoalkyl group mayinclude: 2-aryl-2-oxoethyl group such as 2-phenyl-2-oxoethyl group,2-(1-naphthyl)-2-oxoethyl group, and 2-(2-naphthyl)-2-oxoethyl group,and the like. Examples of an non-nucleophilic counter ion as K⁻ mayinclude: a halide ion such as a chloride ion, a bromide ion or the like,a fluoro alkyl sulfonate such as triflate, 1,1,1-trifluoroethanesulfonate, nonafluoro butane sulfonate and the like, an arylsulfonate such as tosylate, benzene sulfonate, 4-fluorobenzenesulfonate, 1,2,3,4,5-pentafluoro benzene sulfonate and the like, and analkyl sulfonate such as mesylate, butane sulfonate and the like.

(In the formula, R^(102a) and R^(102b) each represent a linear, branchedor cyclic alkyl group having 1–8 carbon atoms. R¹⁰³ represents a linear,branched or cyclic alkylene group having 1–10 carbon atoms. R^(104a) andR^(104b) each represent a 2-oxoalkyl group having 3–7 carbon atoms. K⁻represents an non-nucleophilic counter ion.)

Illustrative examples of the above-mentioned R^(102a) and R^(102b) mayinclude: a methyl group, an ethyl group, a propyl group, an isopropylgroup, n-butyl group, sec-butyl group, tert-butyl group, a pentyl group,a hexyl group, a heptyl group, an octyl group, a cyclopentyl group, acyclohexyl group, a cyclopropylmethyl group, 4-methylcyclohexyl group, acyclohexyl methyl group and the like. Examples of R¹⁰³ may include: amethylene group, an ethylene group, a propylene group, a butylene group,a pentylene group, a hexylene group, a heptylene group, an octylenegroup, a nonylene group, 1,4-cyclohexylene group, 1,2-cyclohexylenegroup, 1,3-cyclopentylene group, 1,4-cyclooctylene group,1,4-cyclohexane dimethylene group and the like. Examples of R^(104a) andR^(104b) may include: 2-oxopropyl group, 2-oxocyclopentyl group,2-oxocyclohexyl group, 2-oxocycloheptyl group and the like. As K⁻, thesame as mentioned in the formulae (P1a-1) and (P1a-2) can beexemplified.

(In the fromula, R¹⁰⁵ and R¹⁰⁶ represent a linear, branched or cyclicalkyl group or alkyl-halide group having 1–12 carbon atoms, an arylgroup or aryl-halide group having 6–20 carbon atoms, or an aralkyl grouphaving 7–12 carbon atoms.)

Examples of the alkyl group as R¹⁰⁵ and R¹⁰⁶ may include: a methylgroup, an ethyl group, a propyl group, an isopropyl group, n-butylgroup, sec-butyl group, tert-butyl group, a pentyl group, a hexyl group,a heptyl group, an octyl group, an amyl group, a cyclopentyl group, acyclohexyl group, a cycloheptyl group, a norbornyl group, an adamantylgroup and the like. Examples of the alkyl-halide group as R¹⁰⁵ and R¹⁰⁶may include: trifluoromethyl group, 1,1,1-trifluoroethyl group,1,1,1-trichloroethyl group, a nonafluoro butyl group and the like.Examples of the aryl group as R¹⁰⁵ and R¹⁰⁶ may include: a phenyl group,an alkoxyphenyl group such as p-methoxyphenyl group, m-methoxyphenylgroup, o-methoxyphenyl group, an ethoxyphenyl group, p-tert-butoxyphenylgroup, m-tert-butoxyphenyl group and the like, and an alkylphenyl groupsuch as 2-methylphenyl group, 3-methylphenyl group, 4-methylphenylgroup, an ethylphenyl group, 4-tert-butylphenyl group, 4-butylphenylgroup, a dimethylphenyl group and the like. Examples of the aryl-halidegroup of R¹⁰⁵ and R¹⁰⁶ may include: a fluorophenyl group, a chlorophenylgroup, 1,2,3,4,5-pentafluoro phenyl group and the like. Examples of thearalkyl group of R¹⁰⁵ and R¹⁰⁶ may include: a benzyl group, a phenethylgroup, and the like.

(In the formula, R¹⁰⁷, R¹⁰⁸ and R¹⁰⁹ represents a linear, branched orcyclic alkyl group or halogenated alkyl group having 1 to 12 carbonatoms, an aryl group or a halogenated aryl group having 6 to 20 carbonatoms, or an aralkyl group having 7 to 12 carbon atoms. R¹⁰⁸ and R¹⁰⁹may bond to each other to form a cyclic structure. When they form acyclic structure, R¹⁰⁸ and R¹⁰⁹ each represent a linear or branchedalkylene group having 1 to 6 carbon atoms. R¹⁰⁵ represents the same asthat of the formula P2.)

Examples of the alkyl group, the halogenated alkyl group, the arylgroup, the halogenated aryl group, and the aralkyl group as R¹⁰⁷, R¹⁰⁸and R¹⁰⁹ may be the same as exemplified for R¹⁰⁵ and R¹⁰⁶. In addition,as an alkylene group for R¹⁰⁸ and R¹⁰⁹, a methylene group, an ethylenegroup, a propylene group, a butylene group, a hexylene group and thelike may be exemplified.

(In the formula, R^(101a) and R^(101b) are the same as explained above.)

(In the formula, R¹¹⁰ represents an arylene group having 6–10 carbonatoms, an alkylene group having 1–6 carbon atoms or an alkenylene grouphaving 2–6 carbon atoms. Some or all of hydrogen atoms of these groupsmay be further substituted with a linear or branched alkyl group or analkoxy group having 1–4 carbon atoms, a nitro group, an acetyl group, ora phenyl group. R¹¹¹ represents a linear, branched or substituted alkylgroup, alkenyl group or alkoxy alkyl group having 1–8 carbon atoms, aphenyl group or a naphthyl group. Some or all of hydrogen atoms of thesegroups may be substituted with an alkyl group or an alkoxy group having1–4 carbon atoms; a phenyl group which may be substituted with an alkylgroup or an alkoxy group having 1–4 carbon atoms, a nitro group or anacetyl group; a hetero aromatic group having 3–5 carbon atoms; or achlorine atom or a fluorine atom.)

Examples of the arylene group as R¹¹⁰ may include: 1,2-phenylene group,1,8-naphtylene group and the like. Examples of the alkylene group mayinclude: a methylene group, an ethylene group, a trimethylene group, atetramethylene group, a phenylethylene group, a norbornane 2,3-di-ylgroup, and the like. Examples of the alkenylene group may include:1,2-vinylene group, 1-phenyl-1,2-vinylene group, 5-norbornene-2,3-di-ylgroup and the like. Examples of the alkyl group as R¹¹¹ may be the sameas exemplified for R^(101a)–R^(101c). Examples of the alkenyl group asR¹¹¹ may include: a vinyl group, 1-propenyl group, an allyl group,1-butenyl group, 3-butenyl group, an isoprenyl group, 1-pentenyl group,3-pentenyl group, 4-pentenyl group, a dimethyl allyl group, 1-hexenylgroup, 3-hexenyl group, 5-hexenyl group, 1-heptenyl group, 3-heptenylgroup, 6-heptenyl group, 7-octenyl group and the like. Examples of thealkoxy alkyl group may include: a methoxy methyl group, an ethoxy methylgroup, a propoxy methyl group, a butoxy methyl group, a pentyloxy methylgroup, a hexyloxy methyl group, a heptyloxy methyl group, a methoxyethyl group, an ethoxy ethyl group, a propoxy ethyl group, a butoxyethyl group, pentyloxy ethyl group, a hexyloxy ethyl group, a methoxypropyl group, ethoxy propyl group, a propoxy propyl group, a butoxypropyl group, a methoxy butyl group, an ethoxy butyl group, a propoxybutyl group, a methoxy pentyl group, an ethoxy pentyl group, a methoxyhexyl group, a methoxy heptyl group and the like.

In addition, examples of the alkyl group having 1–4 carbon atoms withwhich the hydrogen atoms may be further substituted may include: amethyl group, an ethyl group, a propyl group, an isopropyl group,n-butyl group, an isobutyl group, a tert-butyl group and the like.Examples of the alkoxy group having 1–4 carbon atoms may include: amethoxy group, an ethoxy group, a propoxy group, an isopropoxy group,n-butoxy group, an isobutoxy group, a tert-butoxy group and the like.Examples of the phenyl group which may be substituted with an alkylgroup and an alkoxy group having 1–4 carbon atoms, a nitro group or anacetyl group may include: a phenyl group, a tolyl group, p-tert-butoxyphenyl group, p-acetyl phenyl group, p-nitrophenyl group and the like.Examples of a hetero aromatic group having 3–5 carbon atoms may include:a pyridyl group, a furyl group and the like.

Illustrative examples of an acid generator follow. Examples of the oniumsalt may include: diphenyl iodonium trifluoromethane sulfonate,(p-tert-butoxyphenyl)phenyl iodonium trifluoromethane sulfonate,diphenyliodonium p-toluenesulfonate,(p-tert-butoxyphenyl)phenyliodionium p-toluenesulfonate,triphenylsulfonium trifluoromethane sulfonate, (p-tert-butoxyphenyl)diphenyl sulfonium trifluoromethane sulfonate, bis(p-tert-butoxyphenyl)phenyl sulfonium trifluoromethane sulfonate, tris(p-tert-butoxyphenyl)sulfonium trifluoromethane sulfonate, triphenyl sulfoniump-toluenesulfonate, (p-tert-butoxy phenyl)diphenyl sulfoniump-toluenesulfonate, bis(p-tert-butoxy phenyl)phenyl sulfoniump-toluenesulfonate, tris(p-tert-butoxy phenyl)sulfoniump-toluenesulfonate, triphenyl sulfonium nonafluoro butane sulfonate,triphenyl sulfonium butane sulfonate, trimethyl sulfoniumtrifluoromethane sulfonate, trimethyl sulfonium p-toluenesulfonate,cyclohexyl methyl (2-oxocyclohexyl)sulfonium trifluoromethane sulfonate,cyclohexyl methyl (2-oxo cyclohexyl)sulfonium p-toluenesulfonate,dimethyl phenyl sulfonium trifluoromethane sulfonate, dimethyl phenylsulfonium p-toluenesulfonate, dicyclohexyl phenyl sulfoniumtrifluoromethane sulfonate, dicyclohexyl phenyl sulfoniump-toluenesulfonate, trinaphthylsulfonium trifluoromethane sulfonate,(2-norbonyl)methyl (2-oxocyclohexyl)sulfonium trifluoromethanesulfonate, ethylene bis[methyl(2-oxocyclopentyl)sulfoniumtrifluoromethane sulfonate], 1,2′-naphthyl carbonyl methyltetrahydrothiophenium triflate, and the like.

Examples of the diazomethane derivative may include: bis(benzenesulfonyl)diazomethane, bis(p-toluene sulfonyl)diazomethane, bis(xylenesulfonyl)diazomethane, bis(cyclohexyl sulfonyl)diazomethane,bis(cyclopentyl sulfonyl)diazomethane, bis(n-butylsulfonyl)diazomethane,bis(isobutyl sulfonyl)diazomethane, bis(sec-butylsulfonyl)diazomethane,bis(n-propylsulfonyl)diazomethane, bis(isopropyl sulfonyl)diazomethane,bis(tert-butyl-sulfonyl)diazomethane, bis(n-amylsulfonyl)diazomethane,bis(isoamylsulfonyl)diazomethane, bis(sec-amylsulfonyl)diazomethane,bis(tert-amylsulfonyl)diazomethane,1-cyclohexylsulfonyl-1-(tert-butylsulfonyl)diazomethane, 1-cyclohexylsulfonyl-1-(tert-amyl sulfonyl)diazomethane, 1-tert-amylsulfonyl-1-(tert-butylsulfonyl)diazomethane and the like.

Examples of the glyoxime derivative may include: bis-O-(p-toluenesulfonyl)-α-dimethylglyoxime, bis-O-(p-toluene sulfonyl)-α-diphenylglyoxime, bis-O-(p-toluene sulfonyl)-α-dicyclohexyl glyoxime,bis-O-(p-toluene sulfonyl)-2,3-pentanedione glyoxime, bis-O-(p-toluenesulfonyl)-2-methyl-3,4-pentanedione glyoxime, bis-O-(n-butanesulfonyl)-α-dimethylglyoxime, bis-O-(n-butane sulfonyl)-α-diphenylglyoxime, bis-O-(n-butane sulfonyl)-α-dicyclohexyl glyoxime,bis-O-(n-butane sulfonyl)-2,3-pentanedione glyoxime, bis-O-(n-butanesulfonyl)-2-methyl-3,4-pentanedione glyoxime, bis-O-(methanesulfonyl)-α-dimethylglyoxime, bis-O-(trifluoromethanesulfonyl)-α-dimethylglyoxime, bis-O-(1,1,1-trifluoro ethanesulfonyl)-α-dimethylglyoxime, bis-O-(tert-butanesulfonyl)-α-dimethylglyoxime, bis-O-(perfluoro octanesulfonyl)-α-dimethylglyoxime, bis-O-(cyclohexanesulfonyl)-α-dimethylglyoxime, bis-O-(benzenesulfonyl)-α-dimethylglyoxime, bis-O-(p-fluorobenzenesulfonyl)-α-dimethylglyoxime, bis-O-(p-tert-butylbenzenesulfonyl)-α-dimethylglyoxime, bis-O-(xylenesulfonyl)-α-dimethylglyoxime, bis-O-(camphorsulfonyl)-α-dimethylglyoxime and the like.

Examples of the bissulfone derivative may include: bis naphthyl sulfonylmethane, bistrifluoro methyl sulfonyl methane, bis methyl sulfonylmethane, bis ethyl sulfonyl methane, bis propyl sulfonyl methane, bisisopropyl sulfonyl methane, bis-p-toluene sulfonyl methane, bis benzenesulfonyl methane and the like.

Examples of the β-ketosulfone derivative may include: 2-cyclohexylcarbonyl-2-(p-toluene sulfonyl)propane, 2-isopropylcarbonyl-2-(p-toluene sulfonyl)propane and the like.

Examples of the disulfone derivative may include: diphenyl disulfonederivative, a diyclohexyl disulfone derivative and the like.

Examples of the nitro benzyl sulfonate derivative may include:2,6-dinitro benzyl p-toluenesulfonate, 2,4-dinitro benzylp-toluenesulfonate, and the like.

Examples of the sulfonate derivative may include: 1,2,3-tris(methanesulfonyloxy)benzene, 1,2,3-tris(trifluoromethane sulfonyloxy)benzene,1,2,3-tris(p-toluene sulfonyloxy)benzene, and the like.

Examples of the sulfonate derivative of N-hydroxy imide compound mayinclude: N-hydroxy succinimide methane sulfonate, N-hydroxy succinimidetrifluoromethane sulfonate, N-hydroxy succinimide ethane sulfonate,N-hydroxy succinimide 1-propane sulfonate, N-hydroxy succinimide2-propane sulfonate, N-hydroxy succinimide 1-pentane sulfonate,N-hydroxy succinimide 1-octane sulfonate, N-hydroxy succinimidep-toluenesulfonic-acid ester, N-hydroxy succinimide p-methoxybenzenesulfonate, N-hydroxy succinimide 2-chloroethane sulfonate, N-hydroxysuccinimide benzenesulfonic-acid ester, N-hydroxysuccinimide-2,4,6-trimethyl benzene sulfonate, N-hydroxy succinimide1-naphthalene sulfonate, N-hydroxy succinimide 2-naphthalene sulfonate,N-hydroxy-2-phenyl succinimide methane sulfonate, N-hydroxy maleimidemethane sulfonate, N-hydroxy maleimide ethane sulfonate,N-hydroxy-2-phenyl maleimide methane sulfonate, N-hydroxy glutarimidemethane sulfonate, N-hydroxy glutarimide benzenesulfonic-acid ester,N-hydroxy phthalimide methane sulfonate, N-hydroxy phthalimidebenzenesulfonic-acid ester, N-hydroxy phthalimide trifluoromethanesulfonate, N-hydroxy phthalimide p-toluenesulfonic-acid ester, N-hydroxynaphthalimide methane sulfonate, N-hydroxy naphthalimidebenzenesulfonic-acid ester, N-hydroxy-5-norbornene-2,3-dicarboxyimidomethane sulfonate, N-hydroxy-5-norbornene-2,3-dicarboxyimidotrifluoromethane sulfonate, N-hydroxy-5-norbornene-2,3-dicarboxyimidop-toluenesulfonate and the like.

Preferable examples thereof may include: the onium salt such astriphenyl sulfonium trifluoromethane sulfonate, (p-tert-butoxyphenyl)diphenyl sulfonium trifluoromethane sulfonate, tris(p-tert-butoxyphenyl)sulfonium trifluoromethane sulfonate, triphenyl sulfoniump-toluenesulfonate, (p-tert-butoxy phenyl)diphenyl sulfoniump-toluenesulfonate, tris(p-tert-butoxy phenyl)sulfoniump-toluenesulfonate, trinaphthylsulfonium trifluoromethane sulfonate,cyclohexyl methyl (2-oxocyclohexyl)sulfonium trifluoromethane sulfonate,(2-norbonyl)methyl (2-oxocyclohexyl)sulfonium trifluoromethanesulfonate, 1,2′-naphthyl carbonylmethyl tetrahydrothiophenium triflate,and the like;

the diazomethane derivative such as bis(benzene sulfonyl)diazomethane,bis(p-toluene sulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(n-butylsulfonyl)diazomethane, bis(isobutylsulfonyl)diazomethane, bis(sec-butylsulfonyl) diazomethane, bis(n-propylsulfonyl)diazomethane, bis(isopropyl sulfonyl)diazomethane,bis(tert-butylsulfonyl)diazomethane and the like;

the glyoxime derivative such as bis-O-(p-toluenesulfonyl)-α-dimethylglyoxime and bis-O-(n-butanesulfonyl)-α-dimethylglyoxime and the like;

the bissulfone derivative such as bisnaphthyl sulfonyl methane;

a sulfonate derivative of N-hydroxyimide compound such as N-hydroxysuccinimide methane sulfonate, N-hydroxy succinimide trifluoromethanesulfonate, N-hydroxy succinimide 1-propane sulfonate, N-hydroxysuccinimide 2-propane sulfonate, N-hydroxy succinimide 1-pentanesulfonate, N-hydroxy succinimide p-toluene sulfonate, N-hydroxynaphthalimide methane sulfonate and N-hydroxy naphthalimide benzenesulfonate.

The above-mentioned acid generator may be used alone or in admixture oftwo or more kinds of them. The onium salt is excellent in an effect ofachieving a straight wall profile. The diazomethane derivative and theglyoxime derivative are excellent in an effect of reducing standingwave. Therefore, if both of them are combined, minute control of profilecan be conducted.

An amount of the acid generator to be added is preferably 0.1 to 50parts (parts by weight, hereinafter represents the same meaning), morepreferably 0.5 to 40 parts to 100 parts of a base polymer. If it isfewer than 0.1 parts, an amount of acid generated in exposure is few,and sensitivity and resolution is inferior in some cases. If it exceeds50 parts, transmittance of the resist is lowered, and resolution isinferior in some cases.

The dissolution inhibitor (dissolution control agent) blended in thepositive-resist composition of the present invention, especiallychemically amplified positive-resist composition may be a compound whichhas an average molecular weight of 100 to 1,000, preferably 150 to 800.And the compound may have two or more phenolic hydroxyl group in amolecular in which 0 to 100 mole % on average of hydrogens of thephenolic hydroxyl groups are substituted with an acid labile group. Orthe compound may have carboxyl groups in a molecular in which 50 to 100mole % on average of hydrogens of the carboxyl groups are substitutedwith an acid labile group.

A substitution ratio of hydrogens of phenolic hydroxyl groupssubstituted with acid labile group is 0 mole % or more, preferably 30mole % or more on average to total phenolic hydroxyl group. The upperlimit thereof is 100 mole %, preferably 80 mole %. A substitution ratioof hydrogen of carboxyl groups substituted with acid labile group is 50mole % or more, preferably 70 mole % or more on average to totalcarboxyl group. The upper limit thereof is 100 mole %.

In this case, the compound having two or more phenolic hydroxyl groupsor the compound having carboxyl groups may be those represented by thefollowing formula (D1) to (D14).

In the formulae, R²⁰¹ and R²⁰² each represents a hydrogen or a linear orbranched alkyl group or alkenyl group having 1–8 carbon atoms. R²⁰³represents a hydrogen, a linear or branched alkyl group or alkenylgroup, or —(R²⁰⁷)_(h)COOH. R²⁰⁴ represents —(CH₂)_(i)—(i=2 to 10), anarylene group having 6–10 carbon atoms, a carbonyl group, a sulfonylgroup, an oxygen atom or a sulfur atom. R²⁰⁵ represents an alkylenegroup having 1–10 carbon atoms, an arylene group having 6–10 carbonatoms, a carbonyl group, a sulfonyl group, an oxygen atom or a sulfuratom. R²⁰⁶ represents a hydrogen atom, a linear or branched alkyl groupor alkenyl group having 1–8 carbon atoms, or a phenyl group or anaphthyl group which are substituted with a hydroxyl group respectively.R²⁰⁷ represents a linear or branched alkylene group having 1–10 carbonatoms. R²⁰⁸ represents a hydrogen atom or a hydroxyl group. j is aninteger of 0 to 5. u and h are 0 or 1. s, t, s′,t′,s″ and t″ are thenumber satisfying the formula: s+t=8, s′+t′=5, s″+t″=4, such that atleast one hydroxyl group is contained in each of phenyl skeletons. α isthe number such that a molecular weight of the compound represented by(D8), (D9) may be 100 to 1000.

The weight average molecular weight of the above-mentioned compound is100 to 1000, preferably 150 to 800. The amount of the dissolutioninhibitor to be blended is 0 to 50 parts by weight, preferably 5 to 50parts by weight, more preferably 10 to 30 parts by weight, to parts byweight of a base resin. The dissolution inhibitor may be used alone orin admixture of two or more kinds of them. If the amount to be blendedis too few, resolution cannot be improved in some cases. If it is toomuch, a film loss in a pattern may be caused, and resolution tends to belowered.

Furthermore, the basic compound can be blended in the positive resistcomposition of the present invention, especially the chemicallyamplified positive-resist composition.

Suitable compound as the basic compound is a compound which can controldiffusion rate of the acid generated by acid generator when it isdiffused in the resist film. If the basic compound is blended, thediffusion rate of the acid in the resist film can be controlled, andthereby the resolution is improved, change of sensitivity after exposurecan be suppressed, dependency on the substrate or environment can belowered, and exposure margin, pattern profile or the like can beimproved.

Examples of such a basic compound may include: a primary, secondary andtertiary aliphatic amines, a hybrid amine, an aromatic amine, aheterocyclic amine, a compound containing nitrogen which has a carboxylgroup, a compound containing nitrogen which has a sulfonyl group, acompound containing nitrogen which has a hydroxyl group, a compoundcontaining nitrogen which has a hydroxy phenyl group, an alcoholiccompound containing nitrogen, an amide derivative, an imido derivativeand the like.

Illustrative examples of the primary aliphatic amine may include:ammonia, methylamine, ethylamine, n-propylamine, isopropylamine,n-butylamine, isobutyl amine, sec-butyl amine, tert-butylamine,pentylamine, tert-amylamine, cyclopentyl amine, hexylamine, cyclohexylamine, heptylamine, octylamine, nonylamine, decyl amine, dodecylamine,cetylamine, methylene diamine, ethylenediamine, tetraethylene pentamineand the like. Examples of the secondary aliphatic amine may include:dimethylamine, diethylamine, di-n-propylamine, diisopropyl amine,di-n-butylamine, diisobutyl amine, di-sec-butylamine, dipentylamine,dicyclopentyl amine, dihexyl amine, dicyclohexyl amine, diheptylamine,dioctylamine, dinonylamine, didecylamine, didodecylamine, dicetylamine,N,N-dimethyl methylenediamine, N,N-dimethyl ethylenediamine,N,N-dimethyl tetraethylene pentamine and the like. Examples of thetertiary aliphatic amine may include: trimethylamine, triethylamine,tri-n-propylamine, triisopropyl amine, tri-n-butyl amine, triisobutylamine, tri-sec-butyl amine, tripentyl amine, tricyclopentyl amine,trihexyl amine, tricyclohexyl amine, triheptyl amine, trioctyl amine,trinonyl amine, tridecyl amine, tridodecyl amine, tricetyl amine,N,N,N′,N′-tetra methyl methylene diamine, N,N,N′,N′-tetramethylethylenediamine, N,N,N′,N′-tetramethyl tetraethylene pentamine and thelike.

Examples of the mixed amines include: dimethylethyl amine,methylethylpropyl amine, benzyl amine, phenethyl amine, benzyl dimethylamine and the like.

Examples of the aromatic amines and the heterocyclic amines may include:an aniline derivative (for example, aniline, N-methyl aniline, N-ethylaniline, N-propyl aniline, N,N-dimethylaniline, 2-methyl aniline,3-methyl aniline, 4-methyl aniline, ethyl aniline, propyl aniline,trimethyl aniline, 2-nitroaniline, 3-nitroaniline, 4-nitroaniline,2,4-dinitro aniline, 2,6-dinitro aniline, 3,5-dinitro aniline,N,N-dimethyl toluidine and the like), diphenyl (p-tolyl)amine, methyldiphenylamine, triphenylamine, phenylenediamine, naphthylamine, diaminonaphthalene, a pyrrole derivative (for example, pyrrole, 2H-pyrrole,1-methylpyrrole, 2,4-dimethylpyrrole, 2,5-dimethylpyrrole,N-methylpyrrole, and the like), oxazole derivatives (for example,oxazole, isoxazole and the like), a thiazole derivative (for example,thiazole, isothiazole, and the like), an imidazole derivative (forexample, imidazole, 4-methyl imidazole, 4-methyl-2-phenyl imidazole andthe like), a pyrazole derivative, a furazan derivative, a pyrrolinederivative (for example, pyrroline, 2-methyl-1-pyrroline and the like),a pyrrolidine derivative (for example, pyrrolidine, N-methylpyrrolidine,pyrrolidinone, N-methylpyrolidone and the like), an imidazolinederivative, an imidazolidine derivative, a pyridine derivative (forexample, pyridine, methylpyridine, ethyl pyridine, propyl pyridine,butyl pyridine, 4-(1-butyl pentyl)pyridine, dimethylpyridine,trimethylpyridine, triethyl pyridine, phenyl pyridine, 3-methyl-2-phenylpyridine, 4-tert-butyl pyridine, diphenyl pyridine, benzyl pyridine,methoxy pyridine, butoxy pyridine, dimethoxy pyridine,1-methyl-2-pyridone, 4-pyrrolidino pyridine, 1-methyl-4-phenyl pyridine,2-(1-ethylpropyl)pyridine, amino pyridine, dimethyl amino pyridine andthe like), a pyridazine derivative, a pyrimidine derivative, a pyrazinederivative, a pyrazoline derivative, a pyrazolidine derivative, apiperidine derivative, a piperazine derivative, a morpholine derivative,an indole derivative, an isoindole derivative, a 1H-indazole derivative,an indoline derivative, a quinoline derivative (for example, quinoline,3-quinoline carbonitrile, and the like), an isoquinoline derivative, acinnoline derivative, a quinazoline derivative, a quinoxalinederivative, a phthalazine derivative, a purine derivative, a pteridinederivative, a carbazole derivative, a phenanthridine derivative, anacridine derivative, a phenazine derivative, 1,10-phenanthrolinederivative, an adenine derivative, an adenosine derivative, a guaninederivative, a guanosine derivative, a uracil derivative, a uridinederivative and the like.

Furthermore, examples of the compound containing nitrogen which has acarboxy group may include: aminobenzoic acid, indole carboxylic acid,and an amino acid derivative (for example, nicotinic acid, alanine,arginine, aspartic acid, glutamic acid, glycine, histidine, isoleucine,glycyl leucine, leucine, methionine, phenylalanine, threonine, lysine,3-aminopyrazine-2-carboxylic acid, methoxy alanine) and the like.Examples of the compound containing nitrogen which has a sulfonyl groupmay include: 3-pyridine sulfonic acid, p-toluenesulfonic acid pyridiniumand the like. Examples of the compound containing nitrogen which has ahydroxyl group, the compound containing nitrogen which has a hydroxyphenyl group, and the alcoholic compound containing nitrogen mayinclude: 2-hydroxy pyridine, amino cresol, 2,4-quinoline diol, 3-Indoremethanol hydrate, monoethanolamine, diethanolamine, triethanolamine,N-ethyl diethanolamine, N,N-diethyl ethanolamine, triisopropanol amine,2,2′-iminodiethanol, 2-amino ethanol, 3-amino-1-propanol,4-amino-1-butanol, 4-(2-hydroxyethyl)morpholine,2-(2-hydroxyethyl)pyridine, 1-(2-hydroxyethyl)piperazine,1-[2-(2-hydroxyethoxy)ethyl]piperazine, piperidine ethanol, 1-(2-hydroxyethyl)pyrrolidine, 1-(2-hydroxyethyl)-2-pyrrolidinone,3-piperidinone-1,2-propanediol, 3-pyrrolidino-1,2-propanediol, 8-hydroxyjulolidine, 3-quinuclidinol, 3-tropanol, 1-methyl-2-pyrrolidine ethanol,1-aziridine ethanol, N-(2-hydroxyethyl)phthalimide,N-(2-hydroxyethyl)isonicotinamide, and the like.

Examples of the amide derivative may include: formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methyl acetamide,N,N-dimethylacetamide, propione amide, benzamide, and the like.

Examples of the imido derivative may include: phthalimide, succinimide,maleimide, and the like.

Furthermore, one or more compounds selected from basic compoundsrepresented by following general formula (B)-1 can also be added.N(X)_(n)(Y)_(3−n)  (B)-1

(In the formula, n is 1, 2, or 3. The side chain X may be the same ordifferent, and represent the following general formulae (X)-1 to (X)-3.The side chain Y may be the same or different, and represent a hydrogenatom or a linear, branched or cyclic alkyl group having 1–20 carbonatoms which may contain an ether group or a hydroxyl group. Moreover, Xmay bond to each other and form a ring.

In the formulae, R³⁰⁰, R³⁰², and R³⁰⁵ represent a linear or branchedalkylene group having 1–4 carbon atoms, and R³⁰¹ and R³⁰⁴ represent ahydrogen atom or a linear, branched or cyclic alkyl group having carbonatoms 1–20, which may contain one or more of a hydroxy group, an ethergroup, an ester group, and a lactone ring.

R³⁰³ represents a single bond, or a linear or branched alkylene grouphaving 1–4 carbon atoms, R³⁰⁶ represents a linear, branched or cyclicalkyl group having 1–20 carbon atoms, which may contain one or more of ahydroxy group, an ether group, an ester group, and a lactone ring.

Specific examples of the compound represented by the general formula(B)-1 may be as follows:

Tris(2-methoxy methoxy ethyl)amine, tris{2-(2-methoxyethoxy)ethyl}amine,tris{2-(2-methoxy ethoxy methoxy)ethyl} amine,tris{2-(1-methoxyethoxy)ethyl}amine, tris{2-(1-ethoxyethoxy)ethyl}amine, tris{2-(1-ethoxy propoxy)ethyl}amine,tris[2-{2-(2-hydroxy ethoxy)ethoxy}ethyl]amine,4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane,4,7,13,18-tetraoxa-1,10-diazabicyclo[8.5.5]eicosane,1,4,10,13-tetraoxa-7,16-diazabicyclo octadecane,1-aza-12-crown-4,1-aza-15-crown-5,1-aza-18-crown-6,tris(2-formyloxyethyl)amine, tris(2-acetoxy ethyl)amine,tris(2-propionyloxyethyl)amine, tris(2-butylyloxyethyl)amine,tris(2-isobutyryloxyethyl)amine, tris(2-valeryloxyethyl)amine,tris(2-pivaloyloxyethyl)amine, N,N-bis(2-acetoxyethyl)2-(acetoxyacetoxy)ethylamine,tris(2-methoxycarbonyloxyethyl)amine, tris(2-tert-butoxycarbonyloxyethyl)amine, tris[2-(2-oxo propoxy)ethyl]amine,tris[2-(methoxycarbonyl methyl)oxyethyl]amine,tris[2-(tert-butoxycarbonylmethyloxy)ethyl]amine, tris[2-(cyclohexyloxycarbonylmethyloxy)ethyl]amine, tris(2-methoxycarbonyl ethyl)amine,tris(2-ethoxy carbonyl ethyl)amine, N,N-bis(2-hydroxyethyl)2-(methoxycarbonyl)ethylamine, N,N-bis(2-acetoxyethyl)2-(methoxycarbonyl)ethylamine, N,N-bis(2-hydroxy ethyl)2-(ethoxycarbonyl)ethylamine, N,N-bis(2-acetoxy ethyl)2-(ethoxycarbonyl)ethylamine, N,N-bis(2-hydroxy ethyl)2-(2-methoxy ethoxycarbonyl)ethylamine, N,N-bis(2-acetoxy ethyl)2-(2-methoxy ethoxycarbonyl)ethylamine, N,N-bis(2-hydroxy ethyl)2-(2-hydroxy ethoxycarbonyl)ethylamine, N,N-bis(2-acetoxy ethyl)2-(2-acetoxy ethoxycarbonyl)ethylamine, N,N-bis(2-hydroxyethyl)2-[(methoxycarbonyl)methoxycarbonyl]ethylamine, N,N-bis(2-acetoxyethyl)2-[(methoxycarbonyl)methoxycarbonyl]ethylamine, N,N-bis(2-hydroxyethyl)2-(2-oxo propoxy carbonyl)ethylamine, N,N-bis(2-acetoxyethyl)2-(2-oxo propoxy carbonyl)ethylamine, N,N-bis(2-hydroxyethyl)2-(tetrahydrofurfuryloxycarbonyl)ethylamine, N,N-bis(2-acetoxyethyl)2-(tetrahydrofurfuryloxycarbonyl)ethylamine, N,N-bis(2-hydroxyethyl)2-[(2-oxotetrahydrofuran-3-yl)oxycarbonyl]ethylamine,N,N-bis(2-acetoxyethyl)2-[(2-oxotetrahydrofuran-3-yl)oxycarbonyl]ethylamine,N,N-bis(2-hydroxyethyl)2-(4-hydroxy butoxy carbonyl)ethylamine,N,N-bis(2-formyloxyethyl)2-(4-formyloxybutoxy carbonyl)ethylamine,N,N-bis(2-formyloxyethyl)2-(2-formyloxy ethoxy carbonyl)ethylamine,N,N-bis(2-methoxy ethyl)2-(methoxycarbonyl)ethylamine, N-(2-hydroxyethyl)bis[2-(methoxycarbonyl)ethyl]amine, N-(2-acetoxyethyl)bis[2-(methoxycarbonyl)ethyl]amine, N-(2-hydroxyethyl)bis[2-(ethoxy carbonyl)ethyl]amine, N-(2-acetoxyethyl)bis[2-(ethoxy carbonyl)ethyl]amine,N-(3-hydroxy-1-propyl)bis[2-(methoxycarbonyl)ethyl]amine,N-(3-acetoxy-1-propyl)bis[2-(methoxycarbonyl)ethyl]amine, N-(2-methoxyethyl)bis[2-(methoxycarbonyl)ethyl]amine,N-butylbis[2-(methoxycarbonyl)ethyl]amine, N-butylbis[2-(2-methoxyethoxy carbonyl)ethyl]amine, N-methyl bis(2-acetoxy ethyl)amine, N-ethylbis(2-acetoxy ethyl)amine, N-methyl bis(2-pivaloyloxyethyl)amine,N-ethyl bis[2-(methoxy carbonyloxycarbonyloxy)ethyl]amine, N-ethylbis[2-(tert-butoxycarbonyloxy)ethyl]amine, tris(methoxycarbonylmethyl)amine, tris(ethoxy carbonyl methyl)amine, N-butylbis(methoxycarbonyl methyl)amine, N-hexyl bis(methoxycarbonylmethyl)amine, and a β-(diethylamino)-δ-valerolactone. However they arenot limited thereto.

Furthermore, one or more kinds of a basic compound with a cyclicstructure represented in following general formula (B)-2 can also beadded.

(In the formula, X represents the same as explained above, and R³⁰⁷represents a linear or branched alkylene group having 2–20 carbon atoms,which may contain one or more of a carbonyl group, an ether group, anester group, or a sulfide.)

Illustrative examples of (B)-2 may include: 1-[2-(methoxymethoxy)ethyl]pyrrolidine, 1-[2-(methoxy methoxy)ethyl]piperidine,4-[2-(methoxy methoxy)ethyl]morpholine,1-[2-[(2-methoxyethoxy)methoxy]ethyl]pyrrolidine,1-[2-[(2-methoxyethoxy)methoxy]ethyl]piperidine,4-[2-[(2-methoxyethoxy)methoxy]ethyl] morpholine,2-(1-pyrrolidinyl)ethyl acetate, 2-piperidino ethyl acetate,2-morpholino ethyl acetate, 2-(1-pyrrolidinyl)ethyl formate,2-piperidino ethyl propionate, 2-morpholino ethyl acetoxy acetate,2-(1-pyrrolidinyl)ethyl methoxy acetate,4-[2-(methoxycarbonyloxy)ethyl]morpholine,1-[2-(t-butoxycarbonyloxy)ethyl]piperidine,4-[2-(2-methoxyethoxycarbonyloxy)ethyl]morpholine, methyl3-(1-pyrrolidinyl)propionate, methyl 3-piperidino propionate, methyl3-morpholino propionate, methyl 3-(thiomorpholino)propionate, methyl2-methyl 3-(1-pyrrolidinyl)propionate, ethyl 3-morpholino propionate,methoxycarbonyl methyl 3-piperidino propionate, 2-hydroxy ethyl3-(1-pyrrolidinyl)propionate, 2-acetoxy ethyl 3-morpholino propionate,2-oxo tetrahydrofuran-3-yl 3-(1-pyrrolidinyl)propionate, tetra hydrofurfuryl 3-morpholino propionate, glycidyl 3-piperidino propionate,2-methoxy ethyl 3-morpholino propionate, 2-(2-methoxyethoxy)ethyl3-(1-pyrrolidinyl)propionate, butyl 3-morpholino propionate, cyclohexyl3-piperidino propionate, α-(1-pyrrolidinyl)methyl-γ-butyrolactone,β-piperidino-γ-butyrolactone, β-morpholino-δ-valerolactone, methyl1-pyrrolidinyl acetate, methyl piperidino acetate, methyl morpholinoacetate, methyl thio morpholino acetate, ethyl 1-pyrrolidinyl acetate,2-methoxy ethyl morpholino acetate, and the like.

Furthermore, the basic compound containing a cyano group represented bythe general formulae (B)-3 to (B)-6 can be added.

(In the formulae, X, R³⁰⁷, and n are the same as explained above, andR³⁰⁸ and R³⁰⁹ are the same or different and represent a linear orbranched alkylene group having 1–4 carbon atoms.)

Illustrative examples of the basic compound containing a cyano groupinclude: 3-(diethylamino)propiononitrile, N,N-bis(2-hydroxyethyl)-3-amino propiononitrile, N,N-bis(2-acetoxy ethyl)-3-aminopropiononitrile, N,N-bis(2-formyl oxy-ethyl)-3-amino propiononitrile,N,N-bis(2-methoxy ethyl)-3-amino propiononitrile, N,N-bis[2-(methoxymethoxy)ethyl]-3-amino propiononitrile, methylN-(2-cyanoethyl)-N-(2-methoxy ethyl)-3-amino propionate, methylN-(2-cyanoethyl)-N-(2-hydroxy ethyl)-3-amino propionate, methylN-(2-acetoxy ethyl)-N-(2-cyanoethyl)-3-amino propionate,N-(2-cyanoethyl)-N-ethyl-3-amino propiononitrile,N-(2-cyanoethyl)-N-(2-hydroxy ethyl)-3-amino propiononitrile,N-(2-acetoxy ethyl)-N-(2-cyanoethyl)-3-amino propiononitrile,N-(2-cyanoethyl)-N-(2-formyl oxyethyl)-3-amino propiononitrile,N-(2-cyanoethyl)-N-(2-methoxy ethyl)-3-amino propiononitrile,N-(2-cyanoethyl)-N-[2-(methoxy methoxy)ethyl]-3-amino propiononitrile,N-(2-cyanoethyl)-N-(3-hydroxy-1-propyl)-3-amino propiononitrile,N-(3-acetoxy-1-propyl)-N-(2-cyanoethyl)-3-amino propiononitrile,N-(2-cyanoethyl)-N-(3-formyloxy-1-propyl)-3-amino propiononitrile,N-(2-cyanoethyl)-N-tetra hydro furfuryl-3-amino propiononitrile,N,N-bis(2-cyanoethyl)-3-amino propiononitrile, diethyl aminoacetonitrile, N,N-bis(2-hydroxy ethyl)amino acetonitrile,N,N-bis(2-acetoxy ethyl)amino acetonitrile,N,N-bis(2-formyloxyethyl)amino acetonitrile, N,N-bis(2-methoxyethyl)amino acetonitrile, N,N-bis[2-(methoxy methoxy)ethyl]aminoacetonitrile, methyl N-cyanomethyl-N-(2-methoxy ethyl)-3-aminopropionate, methyl N-cyanomethyl-N-(2-hydroxy ethyl)-3-amino propionate,methyl N-(2-acetoxy ethyl)-N-cyanomethyl-3-amino propionate,N-cyanomethyl-N-(2-hydroxy ethyl)amino acetonitrile, N-(2-acetoxyethyl)-N-(cyanomethyl)amino acetonitrile,N-cyanomethyl-N-(2-formyloxyethyl)amino acetonitrile,N-cyanomethyl-N-(2-methoxy ethyl)amino acetonitrile,N-cyanomethyl-N-[2-(methoxy methoxy)ethyl]amino acetonitrile,N-(cyanomethyl)-N-(3-hydroxy-1-propyl)amino acetonitrile,N-(3-acetoxy-1-propyl)-N-(cyanomethyl)amino acetonitrile,N-cyanomethyl-N-(3-formyloxy-1-propyl)amino acetonitrile,N,N-bis(cyanomethyl)amino acetonitrile, 1-pyrrolidine propiononitrile,1-piperidine propiononitrile, 4-morpholine propiononitrile,1-pyrrolidine acetonitrile, 1-piperidine acetonitrile, 4-morpholineacetonitrile, cyanomethyl 3-diethyl amino propionate, cyanomethylN,N-bis(2-hydroxyethyl)-3-amino propionate, cyanomethylN,N-bis(2-acetoxy ethyl)-3-amino propionate, cyanomethylN,N-bis(2-formyloxy-ethyl)-3-amino propionate, cyanomethylN,N-bis(2-methoxy ethyl)-3-amino propionate, cyanomethylN,N-bis[2-(methoxy methoxy)ethyl]-3-amino propionate,(2-cyanoethyl)3-diethyl amino propionate, (2-cyanoethyl)N,N-bis(2-hydroxy ethyl)-3-amino propionate, (2-cyanoethyl)N,N-bis(2-acetoxyethyl)-3-amino propionate, (2-cyanoethyl)N,N-bis(2-formyloxyethyl)-3-amino propionate, (2-cyanoethyl)N,N-bis(2-methoxy ethyl)-3-amino propionate, (2-cyanoethyl)N,N-bis[2-(methoxy methoxy)ethyl]-3-amino propionate, cyanomethyl1-pyrrolidine propionate, cyanomethyl 1-piperidine propionate,cyanomethyl 4-morpholine propionate, (2-cyanoethyl)1-pyrrolidinepropionate, (2-cyanoethyl)1-piperidine propionate,(2-cyanoethyl)4-morpholine propionate, and the like.

The blending amount of the basic compound in the resist composition ofthe present invention is preferably 0.001 to 2 parts, especially 0.01 to1 parts to 100 parts (parts by weight) of the total base resin. If theamount is fewer than 0.001 parts, the effects achieved by blending aresmall. If the blending amount is more than 2 parts, sensitivity may belowered too much.

As a compound which can be added into the resist composition of thepresent invention and has the group represented by ≡C—COOH in themolecule, one or more kinds of compounds selected, for example from thefollowing I group and II group can be used, but it is not limitedthereto. PED (Post Exposure Delay) stability of a resist is improved,and edge roughness on a nitride board is improved by blending thecomponent.

[I Group]

The compounds wherein some or all hydrogen atoms of phenolic hydroxylgroups of the compound represented by following general formula(A1)–(A10) are substituted with —R⁴⁰¹—COOH(R⁴⁰¹ is a linear or branchedalkylene group having 1–10 carbon atoms), and a mole ratio of thephenolic hydroxyl group (C) and the group (D) represented by ≡C—COOH ina molecule is as follows: C/(C+D)=0.1 to 1.0.

In the formulae, R⁴⁰⁸ represents a hydrogen atom or a methyl group. R⁴⁰²and R⁴⁰³ independently represent a hydrogen atom or a linear or branchedalkyl group or alkenyl group having 1–8 carbon atoms. R⁴⁰⁴ represents ahydrogen atom, a linear or branched alkyl group or alkenyl group having1–8 carbon atoms, or —(R⁴⁰⁹)_(h)—COOR′ group (R′ is a hydrogen atom or—R⁴⁰⁹—COOH). R⁴⁰⁵ represents —(CH₂)_(i)— (i=2–10), an arylene grouphaving 6–10 carbon atoms, a carbonyl group, a sulfonyl group, an oxygenatom, or a sulfur atom. R⁴⁰⁶ represents an alkylene group having 1–10carbon atoms, an arylene group having 6–10 carbon atoms, a carbonylgroup, a sulfonyl group, an oxygen atom, or a sulfur atom. R⁴⁰⁷represents a hydrogen atom, a linear or branched alkyl group or alkenylgroup having 1–8 carbon atoms, or a phenyl group or a naphthyl groupsubstituted with a hydroxyl group. R⁴⁰⁹ represents a linear or branchedalkyl group or alkenyl group having 1–10 carbon atoms, or a —R⁴¹¹—COOHgroup. R⁴¹⁰ represents a hydrogen atom, a linear or branched alkyl groupor alkenyl group having 1–8 carbon atoms, or —R⁴¹¹—COOH group. R⁴¹¹represents a linear or branched alkylene group having 1–10 carbon atoms.h is an integer of 1–4. j is the number of 0 to 3. Each of s1 to s4 andt1 to t4 satisfies s1+t1=8, s2+t2=5, s3+t3=4, and s4+t4=6, and is thenumber so that at least one hydroxyl group exists in each phenylskeleton. u is an integer of 1 to 4. κ is the number so that the weightaverage molecular weight of the compound represented by the formula (A6)may be 1,000–5,000. λ is the number so that the weight average molecularweight of the compound represented by the formula (A7) may be1,000–10,000.

[II Group]

The compounds represented by following general formulae (A11)–(A15).

In the formulae, R⁴⁰², R⁴⁰³, and R⁴¹¹ represent the same meaning asexplained above. R⁴¹² represents a hydrogen atom or a hydroxyl group. s5and t5 are the number which satisfy: s5≧0, t5≧0, and s5+t5=5. h′ is 0 or1.

Illustrative examples of the above compounds may include compoundsrepresented by following general formulae AI-1 to 14 and AII-1 to 10.However, it is not limited thereto.

In the formulae, R″ represents a hydrogen atom or a CH₂COOH group, and10 to 100 mole % of R″ is a CH₂COOH group in each compound. κ and λ showthe same meaning as mentioned above.

An addition amount of the compound which has the group represented by≡C—COOH in the molecule is 0 to 5 parts, preferably 0.1 to 5 parts, morepreferably 0.1 to 3 parts, still more preferably 0.1 to 2 parts to 100parts (by weight) of the base resin. If it is more than 5 parts, aresolution of the resist composition may be lowered in some cases.

The surfactant for improving an application property or the like can befurther added to the positive-resist composition of the presentinvention, especially chemically amplified positive-resist composition.

The surfactant is not limitative. Examples thereof may include: nonionsurfactants such as polyoxyethylene alkyl ethers, such aspolyoxyethylene lauryl ether, polyethylene stearyl ether,polyoxyethylene cetyl ether, polyoxyethylene olein ether or the like;polyoxyethylene alkyl allyl ethers such as polyoxyethylene octylphenolether, polyoxyethylene nonyl phenol or the like; polyoxyethylene polyoxypropylene block copolymers; sorbitan fatty acid esters such as sorbitanmonolaurate, sorbitan monopalmitate, sorbitan monostearate or the like;polyoxyethylene sorbitan fatty acid esters such as polyoxyethylenesorbitan monolaurate, polyoxyethylene sorbitan monopalmitate,polyoxyethylene sorbitanmonostearate, polyoxyethylene sorbitantrioleate, polyoxyethylene sorbitan tristearate; fluorinated surfactantssuch as F-Top EF301, EF303 and EF352 (Tochem Products), Megafac F171,F172, and F173 (manufactured by Dainippon Ink and Chemicals, Inc.),Fluorad FC-430 and FC-431 (manufactured by Sumitomo 3M), AsahiguardAG710, Surflon S-381, S-382, SC101, SC102, SC103, SC104, SC105 andSC106, and Surfynol E1004, KH-10, KH-20, KH-30 and KH-40 (manufacturedby Asahi Glass Co., Ltd.), organo siloxane polymer KP-341, X-70-092,X-70-093 (manufactured by Shin-Etsu Chemical Co., Ltd.), acrylic ormethacrylic Polyflow No. 75, No. 95 (Kyoei Yushi Kagaku Kogyo), and thelike. Preferably, FC430, Surflon S-381, Surfynol E1004, KH-20, and KH-30are exemplified. These may be used alone or in admixture of two or moreof them.

An amount of the surfactant to be added in the positive-resistcomposition of the present invention, especially chemically amplifiedpositive-resist composition, may be 2 parts by weight or less,preferably one parts by weight or less to 100 parts by weight of solidcontent in the resist composition.

In the case of using the positive-resist composition of the presentinvention, especially the chemically amplified positive-resistcomposition containing organic solvent, the polymer which has one ormore of the repeating unit represented by the general formula (1a), therepeating unit represented by the general formula (2a) and the repeatingunit represented by the general formula (3b), and the repeating unitrepresented by the general formula (1c), and an acid generator formanufacture of various integrated circuit, known lithography technologycan be used. However, it is not limited thereto.

For example, the substrate for manufacture of integrated circuit (Si,SiO₂, SiN, SiON, TiN, WSi, BPSG, SOG, an organic antireflection film,Cr, CrO, CrON, MoSi, or the like) is coated with the resist compositionof the present invention, according to an appropriate coating methodsuch as a spin coating, a roll coating, a flow coating, a dip coating, aspray coating, a doctor coating, or the like so that the thickness ofthe coating film may be 0.1 to 2.0 μm. Next, The coating film isprebaked on a hot plate at 60 to 150° C. for 1 to 10 minutes, preferablyat 80–120° C. for 1 to 5 minutes. Subsequently, the intended pattern isexposed through a predetermined mask with light source chosen fromultraviolet ray, far ultraviolet ray, electron beam, X-ray, excimerlaser, γ ray, synchrotron-radiation or the like, preferably at anexposure wavelength of 300 nm or less, more preferably at an exposurewavelength in the range of 180 to 200 nm. It is preferable to exposureso that the exposure dose may be about 1–200 mJ/cm², preferably 10–100mJ/cm². Next, post exposure baking (PEB) is conducted at 60–150° C. for1 to 5 minutes, preferably at 80–120° C. for 1–3 minutes on a hot plate.

Furthermore, the target pattern is preferably formed on a substrate byconducting exposure with a developer of an alkali aqueous solution suchas 0.1 to 5%, preferably 2–3% tetramethylammonium hydroxide (TMAH) orthe like for 0.1–3 minutes, preferably for 0.5–2 minutes according to aconventional method, such as the dip method, the puddle method, thespray method or the like. In addition, the resist composition of thepresent invention is suitable for micropatterning especially with a farultraviolet ray with a wavelength of 254–193 nm, a vacuum ultravioletray with a wavelength of 157 nm, electron beam, soft X ray, X-ray,excimer laser, γ ray, synchrotron-radiation, among the high energybeams, preferably with a high energy beam in the range of 180–200 nm.

Moreover, the resist composition of the present invention can also beapplied to immersion lithography. In ArF immersion lithography, purewater is used as an immersion solvent. In the immersion lithography,exposure is conducted with inserting water between the resist film afterpre-baking and a projection lens. The exposure wavelength is 135 nmwhich is the value divided by 1.43 as an index of refraction index ofwater at a wavelength of 193 nm, and it becomes possible to make awavelength short. It is an important technology for making life time ofArF lithography long as 65 nm node, and the development thereof has beenaccelerated. The lactone ring which has been used conventionally as ahydrophilic group of ArF resist has a solubility in both an alkaliaqueous solution and water. When a lactone with high solubility to wateror an acid anhydride such as maleic anhydride or itaconic anhydride areused as a hydrophilic group, water infiltrates from the surface ofresist by immersion in water, and the problem of swelling of the resistsurface is caused. However, it is considered that influence ofdissolution and swelling due to the above-mentioned immersion is small,since hexafluoro alcohol is dissolved in an alkali aqueous solution, butit is not dissolved in water at all.

EXAMPLE

Although Synthetic examples, Comparative synthetic examples, Examples,and Comparative example will be shown and the present invention will beexplained concretely hereafter, the present invention is not restrictedto the following Examples.

Monomer Synthetic Example 1

300 g of α-(trifluoro methyl)vinyl acetate and 126 g of cyclopentadienewere put into a SUS autoclave with a capacity of 2 L in nitrogen gasflow, and the container was sealed, heated to 160° C., and kept at thetemperature for 48 hours. After cooling with ice and lowering theinternal pressure, the content was transferred to a 2 L Kjeldahl flaskand evaporated under vacuum, to provide 151.4 g of the followingcompound (M-1). The yield was 35.3%.

150 g of the resultant compounds (M-1) was put into a 3 L 4 neck flaskin nitrogen atmosphere, and 585 g of trifluoroacetic acid was droppedlittle by little therein. Then, 10 g of methansulfonic acid was addedfurther little by little, and the reaction was performed at 70° C. for 6hours after completion of addition. It was cooled to the roomtemperature after completion of the reaction, and 1.2 L of hexane wasadded and then the organic layer was washed twice with a saturatedaqueous solution of sodium hydrogencarbonate.

The resultant organic substance obtained by evaporating the organiclayer to dryness with an evaporator was dissolved in 1.5 L of methanol,potassium carbonate was added therein, and it was agitated at the roomtemperature for 10 hours. After removing methanol with an evaporator,the organic substance was dissolved in 1.2 L of ether, and was washedtwice with a saturated aqueous solution of sodium chloride. Theresultant oily residue was purified by silica gel chromatography. As aresult, 90.8 g of the following compound (M-2) was obtained. The yieldwas 67.9%.

84 g of the compound (M-2), 73.5 g of triethylamine, 0.5 g ofphenothiazin and 0.5 g of dimethyl amino pyridine were put into a 3 LKjeldahl flask under nitrogen atmosphere, and they were dissolved in amixed solvent of 500 g of dichloromethane and 200 g of tetrahydrofuran.52.5 g of methacryloyl chloride was dropped therein, after dipping aflask in ice bath. Aging was performed for 5 hours with keeping theflask to be dipped in ice bath. After returning to a room temperature,800 mL of ether was supplied and then 800 mL of water was added further.The organic layer was washed with an aqueous solution of formic acid, asaturated aqueous solution of potassium carbonate and a saturatedaqueous solution of sodium chloride, and then dried with magnesiumsulfate. After concentrated under vacuum with an evaporator, theresultant oily residue was purified by a silica gel chromatography. 83.9g of Monomer 1 was obtained. The yield was 74.7%.

¹H-NMR(DMSO): δ 1.24–2.52 (m, 11H), 4.53 (m, 0.3H), 4.69 (m, 0.7H), 5.66(t, 1H), 5.97–6.04 (m, 2H) ¹⁹F-NMR(DMSO): δ−79.0 (2.1F), −74.5 (0.9F)FT-IR(KBr):3482, 2981, 1716, 1697, 1633, 1450, 1405, 1386, 1330, 1297,1222, 1164, 1130, 1103, 1076, 1045, 1012, 981, 971, 948 cm⁻¹

Monomer Synthetic Example 2

80 g of the following compound (M-3) obtained by a conventional methodsuch as Nakai et al method (Organic Synthesis, volume 76, page 151,1998) and 21 g of cyclopentadiene were put into a SUS autoclave with acapacity of 2 L in nitrogen gas flow, and the container was sealed,heated to 160° C., and kept at the temperature for 48 hours. Aftercooling with ice and lowering the internal pressure, the content wastransferred to a 2 L Kjeldahl flask and evaporated under vacuum, toprovide 75.4 g of the following compound (M-4). The yield was 74.7%.

70 g of the resultant compound (M-4) was put into a 1 L 4 neck flask innitrogen atmosphere, the flask was dipped in ice bath, and 220 ml of 1 Mborane THF solution was dropped little by little therein. Aftercompletion of dropping, the reaction was performed at room temperaturefor 6 hours. Then, the flask was dipped in ice bath, 5 g of water wasdropped therein, 53 ml of 5 N aqueous solution of sodium hydroxide wasdropped therein, and 90 ml of hydrogen peroxide was dropped therein.Then, it was taken out from ice bath and aged at a room temperature for2 hours. Thereafter, the resultant salt was dissolved in 200 ml ofwater, and then the organic layer was separated. The water layer wasextracted with 200 ml of hexane and combined to the organic layer. Theorganic layer was washed twice with a saturated aqueous solution ofsodium sulfite and a saturated aqueous solution of sodium chloride.

The resultant organic substance obtained by drying the organic layerwith magnesium sulfate was dissolved in 500 ml of methanol, potassiumcarbonate was added therein, and it was agitated at the room temperaturefor 10 hours. After removing methanol with an evaporator, the organicsubstance was dissolved in 1 L of ether and was washed twice with asaturated aqueous solution of sodium chloride. The resultant oilyresidue was purified by silica gel chromatography. As a result, 41.5 gof the following compound (M-5) was obtained. The yield was 81.2%.

40 g of the compound (M-5), 29.6 g of triethylamine, 0.2 g ofphenothiazin and 0.2 g of dimethyl amino pyridine were put into a 1 L 4neck flask under nitrogen atmosphere, and they were dissolved in a mixedsolvent of 200 g of dichloromethane and 100 g of tetrahydrofuran. Afterthe flask was dipped in ice bath, 20 g of methacryloyl chloride wasdropped therein and it was aged for 5 hours with being dipped in icebath. After returning to a room temperature, 200 mL of ether was puttherein and then 300 mL of water was added further. The organic layerwas washed with an aqueous solution of formic acid, a saturated aqueoussolution of potassium carbonate and a saturated aqueous water of sodiumchloride, and then dried with magnesium sulfate. After concentratedunder vacuum with an evaporator, the resultant oily residue was purifiedby a silica gel chromatography. 34.0 g of Monomer 2 was obtained. Theyield was 65.7%.

¹H-NMR(DMSO): δ1.44–2.82 (m, 9H), 4.90–5.23 (m, 1H), 5.69–6.06 (m, 2H),7.01–7.39 (br, Total:1H) ¹⁹F-NMR(DMSO): −118.9–116.3 (Total:1F),−110.6–106.3 (Total:1F), −72.1, −72.7, −74.6, −75.3 (Total:3F) FT-IR(NaCl): 3598, 3434, 2991, 2933, 1708, 1635. 1454, 1405, 1378, 1313,1263, 1180, 1135, 1099, 1033, 1010, 991, 956, 939, 921 cm⁻¹

Polymer Synthetic Example 1

To 100 mL flask were added 9.8 g of methacrylicacid-2-ethyl-2-adamantane, 4.3 g of methacrylic acid3-oxo-2,7-dioxatricyclo[4.2.1.0^(4,8)]-9-nonyl, and 16.8 g ofmethacrylic acid 5-hydroxy-5-trifluoromethyl-bicyclo[2.2.1]hept-2-yl(the above-mentioned monomer 1), and 20 g of tetrahydrofuran as asolvent. This reaction container was cooled to −70° C. in nitrogenatmosphere, and deaerating under reduced pressure and flowing ofnitrogen gas were repeated 3 times. 0.2 g of AIBN was added as apolymerization initiator after elevating a temperature to a roomtemperature, and it was allowed to react for 15 hours after elevating atemperature to 60° C. To this reaction solution was added 500 ml ofisopropyl alcohol solution, and a white solid was precipitated. Theobtained white solid was taken by filtration and then dried underreduced pressure at 60° C., and 23.3 g of white polymer was obtained.

The obtained polymer was analyzed by ¹³C, ¹H-NMR and GPC measurement.The following analysis results were obtained.

Copolymerization Ratio

-   methacrylic acid-2-ethyl-2-adamantane:methacrylic acid    3-oxo-2,7-dioxatricyclo[4.2.1.0^(4,8)]-9-nonyl:methacrylic acid    5-hydroxy-5-trifluoromethyl-bicyclo[2.2.1]hept-2-yl=0.40:0.14:0.46-   Weight average-molecular-weight (Mw)=11,200-   Molecular weight distribution (Mw/Mn)=1.78

This polymer is defined as Polymer 1.

Polymer Synthetic Example 2

To 100 mL flask were added 9.8 g of methacrylicacid-2-ethyl-2-adamantane, 10.0 g of methacrylic acid3-oxo-2,7-dioxa-tricyclo[4.2.1.0^(4,8)]-9-nonyl, and 8.8 g ofmethacrylic acid 5-hydroxy-5-trifluoromethyl-bicyclo[2.2.1]hept-2-yl,and 20 g of tetrahydrofuran as a solvent. This reaction container wascooled to −70° C. in nitrogen atmosphere, and deaerating under reducedpressure and flowing of nitrogen gas were repeated 3 times. 0.2 g ofAIBN was added as a polymerization initiator after elevating atemperature to a room temperature, and it was allowed to react for 15hours after elevating a temperature to 60° C. To this reaction solutionwas added 500 ml of isopropyl alcohol solution, and a white solid wasprecipitated. the obtained white solid was taken by filtration and thendried under reduced pressure at 60° C., and 18.3 g of white polymer wasobtained.

The obtained polymer was analyzed by ¹³C, ¹H-NMR and GPC measurement.The following analysis results were obtained.

Copolymerization Ratio

-   methacrylic acid-2-ethyl-2-adamantane:methacrylic acid    3-oxo-2,7-dioxatricyclo[4.2.1.0^(4,8)]-9-nonyl:methacrylic acid    5-hydroxy-5-trifluoromethyl-bicyclo[2.2.1]hept-2-yl=0.38:0.26:0.36-   Weight average-molecular-weight (Mw)=10,200-   Molecular weight distribution (Mw/Mn)=1.74

This polymer is defined as Polymer 2.

Polymer Synthetic Example 3

To 100 mL flask were added 15.8 g of methacrylicacid-1-(1-adamantyl)-1-methylethyl, 4.3 g of methacrylic acid3-oxo-2,7-dioxa-tricyclo[4.2.1.0^(4,8)]-9-nonyl, and 16.8 g ofmethacrylic acid 5-hydroxy-5-trifluoromethyl-bicyclo[2.2.1]hept-2-yl(the above-mentioned Monomer 1), and 20 g. of tetrahydrofuran as asolvent. This reaction container was cooled to −70° C. in nitrogenatmosphere, and deaerating under reduced pressure and flowing ofnitrogen gas were repeated 3 times. 0.2 g of AIBN was added as apolymerization initiator after elevating a temperature to a roomtemperature, and it was allowed to react for 15 hours after elevating atemperature to 60° C. To this reaction solution was added 500 ml ofisopropyl alcohol solution, and a white solid was precipitated. Theobtained white solid was taken by filtration and then dried underreduced pressure at 60° C., and 28.3 g of white polymer was obtained.

The obtained polymer was analyzed by ¹³C, ¹H-NMR and GPC measurement.The following analysis results were obtained.

Copolymerization Ratio

-   methacrylic acid-1-(1-adamantyl)-1-methylethyl:methacrylic acid    3-oxo-2,7-dioxatricyclo[4.2.1.0^(4,8)]-9-nonyl:methacrylic acid    5-hydroxy-5-trifluoromethyl-bicyclo[2.2.1]hept-2-yl=0.40:0.18:0.42-   Weight average-molecular-weight (Mw)=9,800-   Molecular weight distribution (Mw/Mn)=1.68

This polymer is defined as Polymer 3.

Polymer Synthetic Example 4

To 100 mL flask were added 12.3 g of methacrylicacid-2-ethyl-2-adamantane, 15.3 g of methacrylic acid3-oxo-2,7-dioxatricyclo[4.2.1.0^(4,8)]-9-nonyl, and 9.3 g of vinyl ether5-hydroxy-5-trifluoromethyl-bicyclo[2.2.1]hept-2-yl, and 20 g oftetrahydrofuran as a solvent. This reaction container was cooled to −70°C. in nitrogen atmosphere, and deaerating under reduced pressure andflowing of nitrogen gas were repeated 3 times. 0.2 g of AIBN was addedas a polymerization initiator after elevating a temperature to a roomtemperature, and it was allowed to react for 15 hours after elevating atemperature to 60° C. To this reaction solution was added 500 ml ofisopropyl alcohol solution, and a white solid was precipitated. Theobtained white solid was taken by filtration and then dried underreduced pressure at 60° C., and 22.5 g of white polymer was obtained.

The obtained polymer was analyzed by ¹³C, ¹H-NMR and GPC measurement.The following analysis results were obtained.

Copolymerization Ratio

-   methacrylic acid-2-ethyl-2-adamantane: methacrylic acid    3-oxo-2,7-dioxatricyclo[4.2.1.0^(4,8)]-9-nonyl:vinyl ether    5-hydroxy-5-trifluoromethyl-bicyclo[2.2.1]hept-2-yl=0.42:0.38:0.20-   Weight average-molecular-weight (Mw)=14,000-   Molecular weight distribution (Mw/Mn) 1.98

This polymer is defined as Polymer 4.

Polymer Synthetic Example 5

To 100 mL flask were added 12.3 g of methacrylicacid-2-ethyl-2-adamantane, 11.1 g of methacrylic acid5-oxo-4-oxatricyclo[4.2.1.0^(3,7)]nonan-2-yl, and 14.3 g of methacrylicacid 5-hydroxy-5-trifluoromethyl-6,6-difluoro-bicyclo[2.2.1]hept-2-yl(the above-mentioned Monomer 2), and 20 g of tetrahydrofuran as asolvent. This reaction container was cooled to −70° C. in nitrogenatmosphere, and deaerating under reduced pressure and flowing ofnitrogen gas were repeated 3 times. 0.2 g of AIBN was added as apolymerization initiator after elevating a temperature to a roomtemperature, and it was allowed to react for 15 hours after elevating atemperature to 60° C. To this reaction solution was added 500 ml ofisopropyl alcohol solution, and a white solid was precipitated. Theobtained white solid was taken by filtration and then dried underreduced pressure at 60° C., and 22.5 g of white polymer was obtained.

The obtained polymer was analyzed by ¹³C, ¹H-NMR and GPC measurement.The following analysis results were obtained.

Copolymerization Ratio

-   methacrylic acid-2-ethyl-2-adamantane:methacrylic acid    5-oxo-4-oxatricyclo[4.2.1.0^(3,7)]nonan-2-yl:methacrylic acid    5-hydroxy-5-trifluoromethyl-6,6-difluoro-bicyclo[2.2.1]hept-2-yl=0.40:0.40:0.20-   Weight average-molecular-weight (Mw)=13,000 Molecular-   weight distribution (Mw/Mn)=1.78

This polymer is defined as Polymer 5.

Polymer synthetic Example 6

To 100 mL flask were added 14.5 g of methacrylic acid-2-adamantyloxymethyl, 11.1 g of methacrylic acid5-oxo-4-oxa-tricyclo[4.2.1.0^(3,7)]nonan-2-yl, and 14.3 g of methacrylicacid 5-hydroxy-5-trifluoromethyl-6,6-difluoro-bicyclo[2.2.1]hept-2-yl(the above-mentioned Monomer 2), and 20 g of tetrahydrofuran as asolvent. This reaction container was cooled to −70° C. in nitrogenatmosphere, and deaerating under reduced pressure and flowing ofnitrogen gas were repeated 3 times. 0.2 g of AIBN was added as apolymerization initiator after elevating a temperature to a roomtemperature, and it was allowed to react for 15 hours after elevating atemperature to 60° C. To this reaction solution was added 500 ml ofisopropyl alcohol solution, and a white solid was precipitated. Theobtained white solid was taken by filtration and then dried underreduced pressure at 60° C., and 22.5 g of white polymer was obtained.

The obtained polymer was analyzed by ¹³C, ¹H-NMR and GPC measurement.The following analysis results were obtained.

Copolymerization Ratio

-   methacrylic acid-2-adamantyloxy methyl:methacrylic acid    5-oxo-4-oxatricyclo[4.2.1.0^(3,7)]nonan-2-yl:methacrylic acid    5-hydroxy-5-trifluoromethyl-6,6-difluoro-bicyclo[2.2.1]hept-2-yl=0.31:0.43:0.26-   Weight average-molecular-weight (Mw)=11,500-   Molecular weight distribution (Mw/Mn)=1.74

This polymer is defined as Polymer 6.

Polymer Synthetic Example 7

To 100 mL flask were added 12.3 g of methacrylicacid-2-ethyl-2-adamantane, 8.6 g of methacrylic acid methoxy isobutyl,18.5 g of methacrylic acid-3-hydroxy-1-adamantyl, and 20.5 g ofmethacrylic acid5-hydroxy-5-trifluoromethyl-6,6-difluoro-bicyclo[2.2.1]hept-2-yl (theabove-mentioned Monomer 2), and 20 g of tetrahydrofuran as a solvent.This reaction container was cooled to −70° C. in nitrogen atmosphere,and deaerating under reduced pressure and flowing of nitrogen gas wererepeated 3 times. 0.2 g of AIBN was added as a polymerization initiatorafter elevating a temperature to a room temperature, and it was allowedto react for 15 hours after elevating a temperature to 60° C. To thisreaction solution was added 500 ml of isopropyl alcohol solution, and awhite solid was precipitated. The obtained white solid was taken byfiltration and then dried under reduced pressure at 60° C., and 22.5 gof white polymer was obtained.

The obtained polymer was analyzed by ¹³C, ¹H-NMR and GPC measurement.The following analysis results were obtained.

Copolymerization Ratio

-   methacrylic acid-2-ethyl-2-adamantane:methacrylic acid methoxy    isobutyl:methacrylic acid-3-hydroxy-1-adamantyl:methacrylic acid    5-hydroxy-5-trifluoromethyl-6,6-difluoro-bicyclo[2.2.1]hept-2-yl=0.20:0.10:0.29:0.41-   Weight average-molecular-weight (Mw)=9,700-   Molecular weight distribution (Mw/Mn)=1.58

This polymer is defined as Polymer 7.

Comparative Synthetic Example 1

24.4 g of methacrylic acid-2-ethyl-2-adamantane and 17.1 g ofmethacrylic acid γ butyrolactone, and 40 g of tetrahydrofuran as asolvent were added in 100 mL flask. This reaction container was cooledto −70° C. under nitrogen atmosphere, and deaerating under reducedpressure and flowing of nitrogen gas were repeated 3 times. 0.2 g ofAIBN was added as a polymerization initiator after elevating atemperature to a room temperature, and it was allowed to react for 15hours after elevating a temperature to 60° C. To this reaction solutionwas added 500 ml of isopropyl alcohol solution, and a white solid wasprecipitated. The obtained white solid was taken by filtration and thendried under reduced pressure at 60° C., and 36.1 g of white polymer wasobtained.

The obtained polymer was analyzed by ¹³C, ¹H-NMR and GPC measurement.The following analysis results were obtained.

Copolymerization Ratio

-   Methacrylic-acid-2-ethyl-2-adamantane:Methacrylic acid γ    butyrolactone=0.48:0.52-   Weight average-molecular-weight (Mw)=12500-   Molecular weight distribution (Mw/Mn)=1.88

This polymer is referred to as Comparative polymer 1.

Examples, Comparative Examples

[Preparation of Positive-Resist Composition]

Using the polymers (Polymers 1–7, Comparative polymer 1), solutions inwhich the components were dissolved at composition shown in thefollowing Table 1 were filtered with a 0.2 μm filter to prepare resistsolutions.

Each composition in Table 1 is as follows. Polymer 1-Polymer 7: obtainedfrom Synthetic examples 1–7 Comparative Polymer 1: obtained fromComparative Example 1 Acid generator: PAG1 (refer to the followingstructural formula)

Basic compound: tributyl amine, triethanolamine TMMEA, AAA, and AACN(refer to the following structural formulae)

Dissolution inhibitor: DRIL (refer to the following structural formula)

Organic solvent: PGMEA (propyleneglycolmonomethylether acetate)[Evaluation of Exposure Patterning]

With each of the prepared resist compositions (Examples 1–12,Comparative example 1) was spin-coated substrate wherein film of AR-19(manufactured by Shipley) with a thickness of 82 nm was formed onsilicon wafer. Then, it was baked for 60 seconds at 130° C. using a hotplate, so that a thickness of the resist may be 250 nm.

It was exposed using the ArF excimer laser stepper (NSR-S305B, NA-0.68,σ0.85, ⅔ annular illumination manufactured by Nicon), it was baked at110° C. for 60 seconds immediately after exposure, development wasperformed for 60 seconds in 2.38% aqueous solution oftetramethylammonium hydroxide, and thus the positive pattern wasobtained.

The obtained resist pattern was evaluated as follows.

Defining the exposure dose which resolves a line and space with 0.12 μmby 1:1 as sensitivity of resist, the minimum line width of the line andspace separated in the exposure dose was defined as resolution of theresist to be evaluated.

Moreover, line edge roughness of a line and space with 0.12 μm wasmeasured using the CD-SEM (S-9220 manufactured by Hitachi Seisakusho).

These results were shown together in Table 1.

TABLE 1 Acid Basic Dissolution Organic Polymer Generator CompoundInhibitor Solvent Line Edge (parts by (parts by (parts by (parts by(part by Sensitivity Resolution Roughness weight) weight) weight)weight) weight) (mJ/cm²) (um) (3σ, nm) Example 1 Polymer 1 PAG1 Tributylamine — PGMEA 32 0.11 7.2 (100) (2.2) (0.2) (800) Example 2 Polymer 2PAG1 Tributyl amine — PGMEA 31 0.11 6.1 (100) (2.2) (0.2) (800) Example3 Polymer 3 PAG1 Tributyl amine — PGMEA 35 0.11 7.8 (100) (2.2) (0.2)(800) Example 4 Polymer4  PAG1 Tributyl amine — PGMEA 28 0.11 7.9 (100)(2.2) (0.2) (800) Example 5 Polymer 5 PAG1 Tributyl amine — PGMEA 260.11 7.2 (100) (2.2) (0.2) (800) Example 6 Polymer 1 PAG1 Triethanol —PGMEA 35 0.11 7.1 (100) (2.2) amine (800)  (0.25) Example 7 Polymer 1PAG1 TMMEA — PGMEA 36 0.10 6.5 (100) (2.2) (0.3) (800) Example 8 Polymer1 PAG1 AAA — PGMEA 36 0.10 6.8 (100) (2.2) (0.3) (800) Example 9 Polymer1 PAG1 AACN — PGMEA 36 0.10 6.8 (100) (2.2) (0.3) (800) Example 10Polymer 1 PAG1 Tributyl amine DRI1 PGMEA 28 0.11 6.3 (100) (2.2) (0.2)(20) (800) Example 11 Polymer 6 PAG1 TMMEA — PGMEA 28 0.10 5.5 (100)(2.2) (0.3) (800) Example 12 Polymer 7 PAG1 TMMEA — PGMEA 31 0.10 6.1(100) (2.2) (0.3) (800) Comparative Comparative PAG1 Tributyl amine —PGMEA 28 0.12 10.5 Example 1 Polymer 1 (2.2) (0.2) (800) (100)

From Table 1, it is clear that the resist compositions of Examples 1–12have high sensitivity, high resolution and reduced line edge roughness.

[Evaluation of Dissolution Characteristic in the Developer by the QCMMethod]

With each of the resist solutions obtained by filtrating the solutionsof the prepared resist compositions (Example 1, Comparative Example 1)with a 0.2 μm filter was spin-coated a quartz board with a size of 1inch (about 2.5 cm) which has an electrode vapor-depositted withchromium on the surface of a ground made of gold. And it was baked for60 seconds at 130° C. using a hot plate, to achieve a resist thicknessof 250 nm.

It was exposed with the ArF aligner ArFES3000 (manufactured by LithoTech Japan), and PEB was performed at 115° C. for 60 seconds. Thesubstrate was installed in Quartz resonator micro balance equipmentRDA-Qz3 (manufactured by Litho Tech Japan) for resist developmentanalyzers, development was performed for 60 seconds in 2.38% aqueoussolution of tetramethylammonium hydroxide, and swelling and dissolutionduring development were measured by the oscillation mode AT cut.Exposure was performed with changing the exposure dose and QCM wasmeasured.

These results are shown in FIG. 1 and FIG. 2. In the drawings, athickness increased to a development time represents swelling, and athickness decreased thereto represents dissolution.

FIG. 1 and FIG. 2 show that swelling measured by the QCM method duringdevelopment is suppressed significantly in the resist composition ofExample 1.

The present invention is not limited to the above-described embodiments.The above-described embodiments are some examples, and those having thesubstantially same composition as that described in the appended claimsand providing the similar action and effects are included in the scopeof the present invention.

1. A polymer which has at least one or more of a repeating unitrepresented by a following general formula (1a), a repeating unitrepresented by a following general formula (2a) and a repeating unitrepresented by a following general formula (3b), and a repeating unitrepresented by a following general formula (1c),

wherein R¹ represents any one of a hydrogen atom, a methyl group and—CH₂CO₂R⁶, R² represents any one of a hydrogen atom, a methyl group and—CO₂R⁶, R¹ and R² in the repeating units (1a) and (2a) may be the sameor different, R³ to R⁵ each independently represent a monovalenthydrocarbon group having 1–15 carbon atoms which may contain a heteroatom, R⁶ represents a hydrogen atom or a linear, branched or cyclicalkyl group having 1–15 carbon atoms, R¹⁵ represents any one of ahydrogen atom, a methyl group and —CH₂CO₂R⁶, R¹⁴ represents any one of ahydrogen atom, a methyl group and —CO₂R⁶, R¹⁶ represents a single bondor a linear or branched alkylene group having 1–4 carbon atoms, R¹⁷represents a fluorine atom or a trifluoro methyl group, R¹⁸ representsany one of a hydrogen atom, an acyl group having 1–10 carbon atoms andan acid labile group, R²¹ and R²² each independently represent ahydrogen atom or a fluorine atom, R²³ and R²⁴ each independentlyrepresent a hydrogen atom or a linear or branched alkyl group having 1–6carbon atoms, R²⁵ is a linear, branched or cyclic alkyl group having1–20 carbon atoms, Y² is —O— or —C(═O)—O—, Z¹ is a bridged cyclichydrocarbon group having 4–10 carbon atoms, which may have —O— and/or—S—, and a1, a2, c, and b3 fall within the range that 0≦a1≦0.8,0≦a2≦0.8, 0≦b3≦0.8, 0.1≦a1+a2+b3≦0.8, and 0<c≦0.9.
 2. The polymeraccording to claim 1 in which the repeating unit represented by thegeneral formula (1c) is a repeating unit represented by a followinggeneral formula,

wherein R¹⁴, R¹⁵, R¹⁶, R¹⁷, R¹⁸, R²¹, R²², Y² and c are the same asmentioned above, and X¹ is any one of a methylene group, an ethylenegroup, an oxygen atom and a sulfur atom.
 3. A positive resistcomposition which contains, at least, the polymer according to claim 2as a base resin.
 4. The positive resist composition according to claim 3which further contains an organic solvent and an acid generator to serveas a chemically amplified resist composition.
 5. The positive resistcomposition according to claim 4 which further contains a dissolutioninhibitor.
 6. The positive resist composition according to claim 5wherein a basic compound and/or a surfactant is further blended as anadditive.
 7. The positive resist composition according to claim 4wherein a basic compound and/or a surfactant is further blended as anadditive.
 8. The positive resist composition according to claim 3 whichfurther contains a dissolution inhibitor.
 9. The positive resistcomposition according to claim 8 wherein a basic compound and/or asurfactant is further blended as an additive.
 10. The positive resistcomposition according to claim 3 wherein a basic compound and/or asurfactant is further blended as an additive.
 11. A positive resistcomposition which contains, at least, the polymer according to claim 1as a base resin.
 12. The positive resist composition according to claim11 which further contains an organic solvent and an acid generator toserve as a chemically amplified resist composition.
 13. The positiveresist composition according to claim 11 which further contains adissolution inhibitor.
 14. The positive resist composition according toclaim 13 wherein a basic compound and/or a surfactant is further blendedas an additive.
 15. The positive resist composition according to claim12 which further contains a dissolution inhibitor.
 16. The positiveresist composition according to claim 15 wherein a basic compound and/ora surfactant is further blended as an additive.
 17. The positive resistcomposition according to claim 12 wherein a basic compound and/or asurfactant is further blended as an additive.
 18. The positive resistcomposition according to claim 11 wherein a basic compound and/or asurfactant is further blended as an additive.
 19. A patterning processcomprising, at least, a step of applying the resist compositionaccording to claim 11 to a substrate, a step of conductingheat-treatment, then a step of exposing the applied resist compositionwith a high energy beam and a step of developing the exposed resistcomposition by using a developer.
 20. The patterning process accordingto claim 19 wherein the high energy beam has a wavelength in the rangeof 180 nm–200 nm.